ARTICLE IN PRESS

0277-3791/$ - se

doi:10.1016/j.qu

�CorrespondE-mail addr

Quaternary Science Reviews 26 (2007) 3406–3422

Ice, moraine, and landslide dams in mountainous terrain

Oliver Korupa,�, Fiona Tweedb

aResearch Unit Avalanches, Debris Flows, and Rock Falls, Swiss Federal Research Institutes WSL/SLF, CH-7260 Davos, SwitzerlandbGeography Department, Staffordshire University, College Road, Stoke on Trent, ST4 2DE, UK

Received 27 April 2007; received in revised form 26 September 2007; accepted 12 October 2007

Abstract

We review recent work on ice, moraine, and landslide dams in mountainous terrain, thus complementing several comprehensive

summaries on glacier dams in intracontinental and Arctic areas of low relief. We discuss the roles of tectonic and climatic forcing on ice-,

moraine-, and landslide-dam formation and sudden drainage, and focus on similarities and differences between their geomorphic impacts

on confined valleys drained by steep bedrock and gravel-bed rivers.

Despite numerous reported failures of natural dams in mountain belts throughout the world, their relevance to long-term dynamics of

mountain rivers remains poorly quantified. All types of dams exert local base-level controls, thus trapping incoming sediment and

inhibiting fluvial bedrock incision. Pervasive geomorphic and sedimentary evidence of outburst events is preserved even in areas of high

erosion rates, suggesting that sudden dam failures are characterized by processes of catastrophic valley-floor aggradation, active-channel

widening, and downstream dispersion of sediment, during which little bedrock erosion seems to be achieved.

We find that, in the absence of direct evidence of former dams, a number of similarities among the geomorphic and sedimentologic

characteristics of catastrophic outburst flows may give rise to ambiguous inferences on the dam-forming process. This is especially the

case for tectonically active mountain belts where there is ample and comparable potential for the formation and failure of ice, moraine,

landslide, and polygenetic dams concomitant with climatic oscillations or earthquake disturbance. Hence, the palaeoclimatic implications

of erroneously inferring the cause of dam formation may be significant.

We recommend that future research on natural dams in mountainous terrain addresses (a) climate- and earthquake-controlled

systematics in the pattern of formation and failure; (b) quantification of response of mountain rivers to catastrophic outburst events and

their concomitant process sequences; (c) elaboration of a comprehensive classification of natural dams in mountainous terrain with

special attention to polygenetic dams; (d) physical-based modelling of dam formation, failure, and routing of water and sediment

outbursts; and (e) quantitative controls on the contribution of natural dams to sediment budgets in mountainous terrain.

r 2007 Elsevier Ltd. All rights reserved.

1. Introduction

The sudden drainage of naturally dammed lakes hascaused some of the largest floods on Earth (O’Connor andCosta, 2004). Catastrophic release of water masses fromice-, moraine-, and landslide-dammed lakes and resultingsediment entrainment has produced floods, hyperconcen-trated flows, and debris flows (Jackson, 1979; Pushkarenkoand Nikitin, 1988; Schuster, 2000; Capart et al., 2001).Such outbursts are single-source events, characterized byextreme runoff with peak discharges of up to 107 m3=s, andflow depths of up to several hundred metres (Baker et al.,

e front matter r 2007 Elsevier Ltd. All rights reserved.

ascirev.2007.10.012

ing author. Tel.: +4181 417 0250; fax: +41 81 417 0110.

ess: korup@slf.ch (O. Korup).

1993; Carling et al., 2002; Magilligan et al., 2002;O’Connor and Costa, 2004). Catastrophic releases of suchgiant volumes of freshwater into the ocean are nowrecognized as potential modulators of ocean circulationpatterns, and hence, contributors to, if not triggers of,Quaternary climatic fluctuations (Andrews and Dunhill,2004; Clarke et al., 2004; Alley and Agustsdottir, 2005).Much of the contemporary knowledge about natural

dam failures derives from a wealth of landforms andsediment facies deemed diagnostic of extreme floodsaccompanying the collapse of Pleistocene ice dams duringterminal continental-scale glaciation (Baker and Bunker,1985; Benito, 1997; Carling et al., 2002; Cutler et al., 2002;Blais-Stevens et al., 2003). Comparable morphologicevidence of megalandforms presumed to be generated by

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–3422 3407

outburst floods has also been detected on Mars (Chapmanet al., 2003; Fairen and Dohm, 2003). Historic occurrencesof catastrophic outbursts, such as the November 1996jokulhlaup on Skeidararsandur, Iceland, have provided theopportunity to obtain detailed process knowledge andrefine physical-based models. There, an eruption in thenewly formed subglacial volcano Gjalp routed meltwaterinto the Grımsvotn caldera, which drained catastrophicallya month after the eruption, thoroughly reshaping a majorsandur (Roberts et al., 2001; Magilligan et al., 2002;Tomasson, 2002; Bjornsson, 2003).

To the present day, there are numerous accounts ofsmaller, but nonetheless destructive, outburst eventsthroughout the world, although the majority of studieshave come from high-latitude or Pleistocene ice-marginalregions (Marren, 2005). Many natural dam failuresalso occur in mountainous terrain. Literature documentingthe existence and failure of ice dams in, for example,the Swiss Alps (Haeberli et al., 2001; Raymond et al.,2003), Alaska (Walder et al., 2006), and BritishColumbia (Geertsema and Clague, 2005) demonstratesthat ice-dammed lakes continue to present persistentand recognized hazards in high-relief terrain. Shresta andShresta (2004) list some 2200 glacial lakes in theNepal Himalaya. More than 20 of these are dammed bymoraines and classified as susceptible to catastrophicoutburst. In the mountains of Nepal and Kazakhstan,disastrous landslide-dam breaks were reported at least onceper every two years on average in the 1970s and 1980s(Khanal et al., 2002). Many of these events have causedhigh numbers of fatalities and large amounts of damage toinfrastructure (Eisbacher and Clague, 1984; Evans andClague, 1994; Shroder Jr., 1998). For example, the failureof a single landslide dam on Dadu River, Sichuan, China,has been the purported cause of an outburst flow that mayhave killed as many as 100,000 people in 1786 (Dai et al.,2005).

Kershaw et al. (2005) pointed out that few studies haveattempted to quantify the geomorphic impact of suchevents on mountain rivers that are typically flanked bysteep, high-relief hillslopes, and that feature bedrock-constricted channels transporting coarse alluvium. Marren(2005) concluded that there was very little understanding ofthe differences between Arctic and alpine proglacial fluvialsystems, especially with respect to high-magnitude and low-frequency floods. These important observations are moti-vation for us to start filling this gap by reviewing recentwork on catastrophic failures of ice, moraine, and landslidedams in mountainous terrain. We recognize that acomprehensive summary of this topic is beyond the scopeof a single article. Rather our objective here is to discussthe implications of formation and failure of natural damsfor fluvial response, palaeoclimate research, and Quatern-ary landscape evolution. These issues appear to be under-reported in the research literature, given that many studiesof natural dams focus on site descriptions and hazardassessments. We briefly discuss likely impacts of climate

change, and conclude with recommendations for futureresearch directions.

2. Terminology and previous reviews

The literature on natural dam breaks has produced awealth of specific terminology. The sudden failure ofglacier, defined here as ice or moraine, dams has beendescribed using several technical terms. The Icelandic termjokulhlaup was coined by Thorarinsson (1939) who referredto a flood caused by rapid drainage of a subglacial lake.Despite this origin, the term is now used to cover aspectrum of flood types originating from glaciers or icesheets (Roberts, 2005), even those induced by intenserainfall (Warburton and Fenn, 1994; Anderson et al.,1999). Glacial lake outburst flood (GLOF) or glacial

outwash flood (Martini et al., 2002) are often usedsynonymously, although they may also refer to processesfollowing moraine-dam failures (Richardson and Rey-nolds, 2000). Glacial floods are also known as debacles inthe Alps, and chhugyumha in Nepal. These regionallyspecific terms attest to both their historic recurrence andpreservation in human memory. The term megaflood

implies quantitative knowledge or estimates of floodvolume 4106 m3 or peak discharge 4106 m3=s (Martiniet al., 2002; Montgomery et al., 2004). A catastrophic flood

or cataclysmic flood (Baker and Bunker, 1985; Benito,1997) is arbitrarily defined as a multiple of a known meanannual flood discharge, whereas superflood (Rudoy, 2002)does not imply any event magnitude. Pal(a)eoflood refers toa flood not recorded in documents or directly measured(Baker et al., 1993). There is no generally acceptedterminology for the sudden failure of landslide dams.Wasson (2003) used the term landslide lake-burst flood

(LLF), and the Nepali word bishyari refers to this processexclusively (Dixit, 2003). Recognizing the importance ofsediment entrainment (flow bulking) during many, if notmost, dam failures, we use the term outburst flow

throughout to encompass the full spectrum from hydro-logical clearwater floods to hyperconcentrated flows todebris flows.Several recent comprehensive reviews summarize current

knowledge on the formation, stability, and failure ofnatural dams. The work of Costa and Schuster (1988)remains an authoritative introduction to this topic, whileCenderelli (2000) also compared the characteristics of flowsfrom natural and artificial dam failures. Tweed and Russell(1999) reviewed the catastrophic drainage of ice-dammedlakes; Roberts (2005) focused on the physics of subglacialjokulhlaup mechanisms, underlining the potential feedbackbetween jokulhlaups and glacial drainage mechanisms.Korup (2002) summarized research on landslide dams sincethe 1990s, and suggested several future research directions.Extreme floods both historic and ancient, as well as theirsedimentologic legacies and geomorphic impacts, havebeen covered in several special volumes (Martini et al.,2002; Herschy, 2002; Snorrason and Finnsdottir, 2002;

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–34223408

O’Connor and Costa, 2004). A large number of data onnatural dams and catastrophic outburst flows have beencompiled in systematic overviews and inventories onparticular regions (Table 1). However, few studies havesystematically addressed the peculiarities of natural damfailures in steep terrain (Bjornsson, 2004) and thegeomorphic consequences for mountain rivers.

3. Ice, moraine, and landslide dams in mountainous terrain

3.1. Formation

Mountain belts host the key prerequisites for theformation of natural dams, including high altitude and

Table 1

Regional studies on ice (I), moraine (M), and landslide (L) dams in

mountainous terrain

Region Types of

dams

covered

Selected references

Worldwide I,L,M Costa and Schuster (1991)

Canadian Cordillera L,M Clague and Evans (1994, 2000)

European Alps I,M,L Haeberli (1983), Eisbacher and

Clague (1984), and Raymond et

al. (2003)

Himalayas I,L,M Mool (1995), Yamada (1998),

Richardson and Reynolds

(2000), and Hewitt (2002)

Southern Siberia I Rudoy (2002), and Herget (2005)

Central Asia I,L,M Pushkarenko and Nikitin (1988),

and Liu (1992)

China L,M Ding and Liu (1992), Chai et al.

(2000), and Dongtao et al. (2004)

South America I,M Lliboutry et al. (1977)

New Zealand L Korup (2004)

Fig. 1. (A) Moraine dam impounding Crucible Lake at the foot of the main div

above lake level. (B) Extensive alluvial fill upstream of the Kalopani rockslide

(C) Coarse debris fan below proglacial gorge, Ala-Archa, Kyrgyz Tien Shan (

relief that allows rapid fluctuations of glaciers; steepslopes; orographically enhanced precipitation; andsteep narrow, confined channels with resistant boundaries.The formation of ice and moraine dams in such terrainis a gradual and often cyclic process linked to the dynamicsof the local glacier mass balance, and hence, forcing byclimatic parameters (Evans and Clague, 1994; Geertsemaand Clague, 2005). Independently of climate, glaciersurging can result in relatively rapid ice-dammed lakeformation and the potential for associated outburstflows (Mayo, 1989). Glacier surface gradient andvelocity may control the rate of lake formation (Quinceyet al., 2007), whereas subglacial hydraulics mainlycontrol ice-dam formation (Roberts, 2005). Evenwhere substantial ice-dammed lakes are absent,blocky sediment entrained during glacier advancesmay block drainage conduits and cause water andsediment outbursts (Davies et al., 2003). Moraine-dammed lakes differ from supra-, sub- or englacial lakesin that they usually form in response to glacialdownwasting during periods of climate warmingfollowing earlier advances (Fig. 1A). Also, moraine-dammed lakes need not be coupled to any activeglacier mass. Clague and Evans (2000) proposed a quasi-cyclical model that relates formation of neoglacial morainedams to an oscillating climate. Yet large terminal morainesdo not necessarily form solely in response to climate-drivenglacier mass balance cycles. They can also result fromchanges in supraglacial debris flux conditioned by lateralsediment input (Benn and Owen, 2002). Larsen et al. (2005)pointed at the possibility of a synchronous origin forseveral Late Holocene moraines in the Southern Alps ofNew Zealand, possibly driven by increased supraglacialsediment production during earthquake-triggered land-sliding episodes.

ide of the Southern Alps, New Zealand (March 2001). Dam crest is �10m

dam (�3 km3), Kali Gandaki River, Nepal Himalaya (September 1995).

June 2004).

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–3422 3409

Conversely, landslide dams mostly form because ofcatastrophic slope failure (Eisbacher and Clague, 1984).Landslide debris supplied to river channels at low ratestends to be more effectively removed by fluvial erosion.Preparatory factors for landsliding include loss of cohesionand internal friction of hillslope materials, and increases inhillslope angle and relief. This may be enhanced by stressrelease along intrinsic zones of weakness; repeated earth-quake shaking; rock-mass shattering along tectonic faultzones; and slope debuttressing following deglaciation orprecursory landsliding. Trigger mechanisms of river-dam-ming landslides include high-intensity rainstorms orsnowmelt events that raise pore- and cleft-water pressuresin soil-mantled and jointed rock slopes, respectively;seismic ground acceleration; or undercutting by naturalerosion or anthropogenic modification.

3.2. Geometry, internal structure, and stability

A growing number of data on natural dams in mountainbelts allows some first-order generalizations on theirgeometry (Tables 1 and 2). The highest, though breached,natural dam documented appears to be that formed by theRondu-Mendi rock avalanche on the Indus River, Paki-stan, with a crest height of 1100m (Hewitt, 2002). Many ofthe largest landslide dams with crest heights 4500m arelocated in large valley trains of Central and High Asia. Inrare cases, dams formed by long-runout rock avalanchesmay bury river reaches 415 km long. The upper size limitsof moraine dams are difficult to quantify, because large

Table 2

Comparison of characteristics of historic and post-glacial ice, moraine, and la

Ice dams Mo

Catchment position Mainly in headwaters Ma

Cause of formation Glacier advance or confluence; subglacial

ponding

Ne

deb

Mode of formation Quasi-periodic to episodic; gradual Qu

Dam height (m) o200 o4

Dam length (m) Unknown Un

Dam width (m) Unknown Un

Material properties Ice Poo

ma

Dam volume (m3) Unknown Un

Lake volume (m3) o109 104

Triggers of outburst Dam flotation; conduit blockage during

advance over coarse sediments; high

temperatures and rainfall

Dis

me

ups

Water volume released

(m3)104–109 104

Peak outburst

discharge (m3=s)102–106 103

Detectable range of

outburst flows (km)

Unknown 101

Sediment outburst

volume (m3)104–106 104

Life span (yr) Unknown 101

latero-frontal moraine ridges that have prograded intointramontane basins often host sizeable ponds perched onsuperficial depressions. Montgomery et al. (2004) reportedvery large moraine dams with heights of several hundredmetres in the Tsangpo River gorge, Tibet. In cross-section,moraine dams generally have smaller width-to-height ratiosthan landslide dams (Costa and Schuster, 1988). Forexample, they are 8:1 for moraine dams in BritishColumbia (McKillop and Clague, 2007), and 20:1 forlandslide dams of various types in New Zealand (Korup,2004). This difference is significant, as the cross-sectionaldam geometry controls the rate of breach processes. It alsogoverns the rate of sediment entrainment by subsequentflows of lesser magnitude until self-armoring or stabiliza-tion toward the angle of repose of the dam material isachieved (Fig. 2).

Little is known about the dimensions and geometry ofsub- or englacial ice dams, let alone the associated drainageconduits, as their delineation often requires detailedgeophysical methods (Roberts, 2005). Moreover, mountainvalleys set constraints on the capacity of ice-dammed lakes.Alaska has the potential for deep ice-dammed lakes, andthere are some very deep ice-dammed lakes in theHimalayas where many tributaries are blocked off by iceto form lakes in deep valleys (Richardson and Reynolds,2000). The behaviour of many ice-dammed lakes is stronglylinked to the nature of the damming ice. Cold polar icetends to be denser than temperate ice, dry at the ice/bedcontact and contains little free water; these attributes resultin a coherent dam less likely to be breached; when such

ndslide dams in mountainous terrain

raine dams Landslide dams

inly in headwaters Unspecified; determined by

local slope stability

gative glacier mass balance; supraglacial

ris flux

Climatic and seismic triggers;

slope undercutting

asi-periodic; gradual Stochastic; mainly

catastrophic

00 o1100

known o6000

known o17; 000rly sorted, massive to stratified bouldery

terial, ice core possible

Poorly sorted, often angular;

dependent on failure process

known 103–1010

–107 106–1010

placement waves; rainfall; excess

ltwater; ice-core meltout and seepage;

tream outburst event

Overtopping; seepage;

displacement waves; gradual

erosion; gravity collapse

–108 105–109

–104 102–105

–103 101–104

–106 103–108

–102 10�2–104

ARTICLE IN PRESS

Fig. 2. (A) Boulder-armored breach channel across a late Holocene rock-

avalanche dam, Crow River, Southern Alps of New Zealand (March

2006). (B) Scree slopes composed of angular rock-avalanche debris mantle

the dissected dam. Exposure is �100m high. (C) Upstream view of breach

channel �500m upstream. Persistent ‘‘knick-slope’’ reach of high-energy

expenditure is characterized by boulder cascades. Vegetation cover on

some boulders indicates limited ability of normal flows to remove bed

armour.

O. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–34223410

lakes drain it is more likely to be by overspilling (Costa andSchuster, 1991; Tweed and Russell, 1999). In temperate ice,the density of the glacier dam, the existence of crevassesand conduits in the ice and the nature of the contactbetween the ice and the substrate constitute importantcontrols on dam stability and the mechanisms of ice-dammed lake drainage (Tweed, 2000).The stability of moraine and landslide dams is a function

of their geometry; internal structure; material propertiesand particle size distribution (Weidinger et al., 2002);volume and rate of water and sediment inflow; and seepageprocesses (Table 2). Reliably assessing the stability ofnatural dams thus requires a geotechnical approach takinginto account a variety of dynamic loading scenarios(Schuster and Alford, 2004; Risley et al., 2006). Meaningfulpredictions depend on knowledge about the exact dam andreservoir geometry. In confined mountain valleys thetopography prior to blockage is often difficult, if notimpossible, to determine, and further hampered by super-position of other geomorphic processes. Multiple land-slides at a site may form stacked dams. At Tsaoling,Taiwan, for example, four major (107–108 m3) rockavalanches have repeatedly dammed Ching-Shui Creek inthe 20th century (Chigira et al., 2003), episodicallyincreasing the debris volume stored on the valley floor.Moreover, impoundments are ephemeral; they initiallygrow as flow is impeded, but subsequently decrease in sizedue to gradual infill. In mountain belts with highdenudation rates landslide- and moraine-dammed lakesare indeed often infilled before the dam is breached (Hickset al., 1990; Korup et al., 2006).Unfortunately, the internal structure of both moraine

and landslide dams mostly becomes evident only after damfailure (Casagli et al., 2003). Geophysical methods such asseismic refraction, electrical resistivity, and gravimetricsoundings provide valuable insights, especially into wateror ice content (Haeberli et al., 2001). It is believed thatdams composed of boulder- or clay-rich debris are lesslikely to fail than those containing unconsolidated orhighly permeable debris (Costa and Schuster, 1988).Wassmer et al. (2004) suggested that major sedimentaryfacies within the comminuted debris of the Flims rockslidedam, Swiss Alps, controlled the rates of incision of its 400-m deep breach canyon. Dynamic fragmentation duringrock avalanching produces such heavily crushed debristopped by a thin angular boulder carapace (Davies andMcSaveney, 2002; Dunning et al., 2006). Once breached,fluvial erosion of comminuted rock-avalanche debris maybe rapid (Korup et al., 2004) (Fig. 2). In contrast, largerock-block slides, which fail as a largely intact mass, canproduce impermeable dams (Davies et al., 2006). Inpermafrost terrain, interstitial ice can occur in bothmoraine and landslide dams (Schuster and Alford, 2004).Such ice cores are sensitive to changes in local thermalregimes not only brought about by climate change, but alsothawing due to meltwater erosion. Measured rates of thaw-induced dam subsidence and gradual dam-crest breaching

ARTICLE IN PRESS

Fig. 3. Reported peak discharge and total outburst volume from historic

(years of occurrence indicated) failures of ice, moraine, and landslide dams

in mountainous terrain.

O. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–3422 3411

by meltwater from proglacial lakes in the Himalayas attainup to 3m/yr (Richardson and Reynolds, 2000; Delisleet al., 2003), although these site-specific rates cannot betaken as representative.

3.3. Failure

Natural debris dams fail when the material strength ofthe dam is exceeded by driving forces that comprise, amongothers, the weight of the impounded water mass, shearstresses because of seepage, overtopping or additionalmomentum of displacement waves. Displacement wavesinduced by landslides, ice avalanches, or glacier calving(seiches) can trigger dam breach at water levels withotherwise sufficient freeboard (Hubbard et al., 2005;Harrison et al., 2006). Richardson and Reynolds (2000)assert that 53% of catastrophic moraine-dam failures in theHimalayas are initiated by such displacement waves. Insome cases most of the water mass has been displacedwithout significant breach-channel incision (Clague andEvans, 2000). In the long-term, lateral input of debris bymass movement and upstream (glacio-)fluvial sedimentalso further reduces the storage capacity and freeboard ofmoraine- and landslide-dammed lakes.

Landslide dams appear to fail mostly by either seepage,overtopping and breaching following meteorologicalfloods, seiches, or upstream outburst flows (Lliboutryet al., 1977; Costa and Schuster, 1988; Schuster, 2000;Hermanns et al., 2004b). The occurrence of large, lateHolocene landslide-dammed lakes in seismically activeregions (Korup, 2004) also points to some resilience of damstability with regard to frequently recurring earthquakes.In cases where failure does occur, partial breaches andmultiple dam failures at a site are not uncommon. In fact,many natural dams are only partly removed by failure orpost-failure surface processes (Korup et al., 2006). Erminiand Casagli (2003) noted that �80% of landslide dams thatreportedly failed, did so within one year after theirformation. However, data on the total proportion oflandslide dams that failed eventually are incomplete, asmany events remain unrecorded. This has caused somemisinterpretations of the stability and longevity of naturaldams. Measures of dam and catchment geometry havebeen used to empirically assess and regionally compare thestability of landslide (Ermini and Casagli, 2003) andmoraine dams (McKillop and Clague, 2007). Yet bothtypes of dams have been shown to be potentially quasi-stable (Hermanns et al., 2004b) for up to 103 yr, beforefailing catastrophically (Clague and Evans, 2000; Hubbardet al., 2005), placing severe limits to empirical approachesto natural dam stability. In contrast, ice dams are usuallyfully obliterated following their failure (Bjornsson, 2004).

Catastrophic meltwater release from ice dams is anepisodic phenomenon controlled by thresholds exceeded insub- and englacial hydraulics, such as breach wideningbetween the damming ice and a valley wall (Walder andCosta, 1996), cyclic flotation or glacier surges (Mayo, 1989;

Anderson et al., 2003). Famous examples include the PeritoMoreno Glacier, which periodically dams Lago Argentino,Patagonia (Warren and Aniya, 1999), and the InylchekGlacier, which releases annual outbursts from LakeMerzbacher, Central Tien Shan (Aizen et al., 1997). Yetfailures of glacier dams are rarely observed in the field(Clague and Evans, 2000), because they often occur inremote and unmonitored terrain. Several reports suggestthat seepage and overtopping are among the less frequentcauses of sudden failure (Vilimek et al., 2005). Some ice-dammed lakes drain in response to the same triggermechanism each time that there is an outburst; however,the dynamics of the jokulhlaup cycle (Evans and Clague,1994) dictate that, in some cases, different drainageinitiation mechanisms may be operating over time for thesame ice-dammed lake. Walder et al. (2006) discuss thedrainage of ice-dammed Hidden Creek Lake, Alaska,arguing that the degree of surface uplift of the ice duringoutbursts cannot be explained by flexure of the glacier.Instead they conclude that uplift occurs as a consequenceof fault-block movement, faults being regularly regeneratedfrom year to year, possibly by the linkage of basal andsurface crevasses. Fluctuations of glacier thickness andposition in response to changing environmental conditions,ice-dammed lake basin bathymetry and water supply allexert control on ice-dammed lake drainage (Tweed andRussell, 1999; Geertsema and Clague, 2005).

3.4. Peak discharge, flow geometry, and stream power

Peak discharge Qp is a key variable in predicting andreconstructing outburst flow routing. Few events have beeninstrumented (Fig. 3). In most cases, Qp may be back-calculated using palaeo-stage indicators (Baker and Bun-ker, 1985; Smith, 1993) together with slope-area methods;hydraulic step-backwater models (Cenderelli and Wohl,2001); critical-depth methods; entrainment velocities forflow-transported boulders; super-elevation geometry; orempirical breach relationships (Coxon et al., 1996; Cutler

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–34223412

et al., 2002; Marren, 2002; Clarke et al., 2004; Kershawet al., 2005). Flow-induced aggradation in bedrock-constrained channels, however, may lead to considerableunderestimates of local cross-sectional areas and otherhydraulic variables (Kershaw et al., 2005). Likewise,hydraulic ponding upstream of bedrock constrictions orephemeral blockage induced by undercut hillslope failurescause local flow attenuation and downstream decrease ofQp (Cenderelli and Wohl, 2003; Kershaw et al., 2005).Also, despite various empirical equations for predicting Qp

from morphometric variables such as dam height, volumeor potential energy of water drained (Walder and Costa,1996; Walder and O’Connor, 1997; Clague and Evans,2000; Kershaw et al., 2005), there is general consensus thatsuch relationships offer moderate reliability at best, withorder-of-magnitude scatter in predictions (Walder andO’Connor, 1997; Dai et al., 2005). Most empirical methodsare limited to water floods and hyperconcentrated flowsonly, and exclude debris-flow phases. For ice dams,however, there are several physical-based approaches thatexplain Qp and hydrograph shape from subglacial melt-water routing (Anderson et al., 2003; Ng and Bjornsson,2003).

Flume experiments of dam-break debris flows suggestthat Qp is a function of clast size; permeability; dam width;and bed slope, while translation and attenuation lead todownstream variations in discharge (Li et al., 2002). Froma detailed geomorphic study of the 1997 Queen Bessmoraine-dam failure, Canada, Kershaw et al. (2005)concluded that this particular outburst event involvedovertopping and a subsequent dam-breach phase. Theyargued that flows resulting from overtopping are char-acterized by high Qp and much more rapid downstreamdischarge attenuation than those resulting from gradual

Fig. 4. LANDSAT TM subscene (3 December 1987; path 135, row 39,

RGB 541) of 17-km long alluvial backwater flat (bw) formed upstream of

rock avalanche/debris-flow dam (df), Yigong Tsangpo River, SE Tibet.

The image was taken 87 years after blockage by the 0:5� 109 m3 landslide

(red arrow shows movement direction of landslide); 13 years later another

similar-sized event blocked the river for several months at the same site.

Image courtesy of Global Land Cover Facility, University of Maryland.

dam breach. Such multi-phase flows in particular posesubstantial problems to numerical flow routing whichcombines dam-breach processes, hydrograph characteris-tics, and channel morphology (Li et al., 2002).Estimates of Qp from historic natural dam breaks are

between 103 and 104 m3=s (Fig. 3), usually exceedingnormal flood discharge by up to two orders of magnitude(Xu, 1981; Tweed and Russell, 1999; Dunning et al., 2006).Historically, the highest reported values of 104–105 m3=scome from landslide-dam breaks in High Asia. The mostrecent occurred on Yigong Tsangpo River, Tibet, in 2000,following failure of a dam formed by one of the largesthistoric landslides in Asia (Fig. 4). This extremely rapidrock/ice avalanche of 3� 108 m3 issued from a steeptributary creek, and transformed into a large debris flow(Shang et al., 2003). Dam failure generated a discharge of1:2� 105 m3=s, estimated 17 km downstream, matchedonly by the largest recorded meteorological floods onEarth (O’Connor and Costa, 2004). About 3� 109m3 ofwater were released, and the flow wave travelled for severalhundred kilometres downstream, causing fatalities andmajor damage in India. This complements earlier reports ofoutbursts from landslide dams in Tibetan headwaters, suchas the 1959 Chayu event, which caused severe flooding inIndian provinces downstream (Dongtao et al., 2004).Similarly, about half of all GLOFs that allegedly occurredin Tibet since the 1930s, mostly impacted on downstreamreaches in Nepal, Bhutan, and India (Dongtao et al., 2004).The volume of water released during historic moraine-

and landslide-dam breaks is often 4106 m3 (Clague andEvans, 2000). Proximal outburst flow depths may readilyattain 100m (King et al., 1989), and remain elevated overlong distances (Fig. 5). For example, flow waves from the1974 Mayunmarca rockslide-dam failure, Peru, remained20m high some 100 km downstream (Walder and O’Con-nor, 1997). Landslide dams appear to form larger lakes andrelease more water on average; they are less restricted toheadwaters, and therefore are likely to accumulate moredischarge. McKillop and Clague (2007), for example,found that in southwestern British Columbia, more thanhalf of over 170 moraine dams occurred in headwater areaswith areaso1 km2. The corresponding figure, derived froma world-wide sample of rockslide dams ðn ¼ 146Þ, is�162 km2. However, damming of trunk streams bytributary glaciers may also occur in lower catchmentpositions; there is some evidence of Holocene morainedams, which may have dammed giant (1011 m3) lakes in theTsangpo River gorge, Tibet (Montgomery et al., 2004).The inferred values of Qp�10

6 m3=s rival those derivedfrom the failure of Pleistocene ice-dammed lakes in theSiberian Altai (Baker et al., 1993; Rudoy, 2002). LakeSarez (1:7� 1010 m3), currently impounded by the 2.2-km2

Usoi rockslide dam in the Tajik Pamir, demonstrates thatsuch large lakes may indeed form in rugged mountainousterrain (Schuster and Alford, 2004).Very few studies have quantified specific stream power

O. Cenderelli and Wohl (2003), for example, showed that

ARTICLE IN PRESS

Fig. 5. Estimated flow depths of selected outburst flows from failures of natural dams.

Fig. 6. Large gravel bar resulting from Pleistocene outburst flow from ice-

dammed lakes, Siberian Altai. Photograph courtesy of J.-H. May.

O. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–3422 3413

back-calculated O for historic GLOFs in the KhumbuHimal, Nepal, ranged between 103 and 104 W=m2. Inbedrock-gorge reaches, maximum values attained abouthalf of those achieved during Pleistocene Missoula floods(Benito, 1997). Cenderelli and Wohl (2003) noted O ¼103 W=m2 and a valley width of �100m as criticalthresholds for deposition and erosion, respectively. Suchthresholds are useful, but valid for specific sites only,encompassed by a range of O ¼ 102–104 W=m2, for largehydrological floods, and hyperconcentrated or debris flows,respectively (Lapointe et al., 1998; Batalla and De Jong,1999).

Sediment entrained during outbursts affects hydraulicsthrough density, viscosity, and turbulence. Sedimentvolumes may be of the same order of magnitude as thatof the volume of water released (Lliboutry et al., 1977;Haeberli, 1983), and in extreme cases, increase discharge bya factor of 410 (Schuster, 2000; Capart et al., 2001). Manydam-break ‘‘floods’’ are indeed sediment-laden water ordebris flows with sediment-water ratios of �1:3 anddensities of up to 2:4 t=m3 (Pushkarenko and Nikitin,1988; King et al., 1989; Schuster, 2000; O’Connor et al.,2001; Chen et al., 2004). Sediment load is also known to behighly transient; some outburst flows have been noted tobecome progressively more fluidal as initially voluminoussediment supply is exhausted (Carrivick et al., 2004b).Channelized outburst debris flows are only generated andmaintained on slopes of 10–15� (Clague and Evans, 2000),but may cause massive deposition at river junctions,temporary blockage, and secondary debris flows fromsubsequent outbursts (Clague and Evans, 2000; Dunning etal., 2006). One of the largest followed the 1914 Barrancasrock-avalanche dam failure on Rio Colorado, Patagonia,which eroded 1:2� 108 m3 of sediment mainly fromthe dam (Hermanns et al., 2004b). It formed terraces ofup to 20m above the channel floor over 60 km, and led tothe damming of several tributaries; the flow travelled1250 km as far as the Atlantic coast. Massive entrainment

is also reported for the 1858 rockslide-dam break atGhammessar, Hunza River, Pakistan, which triggered alarge (1:3� 108 m3) retrogressive slump of the dam face(Shroder Jr., 1998).

3.5. Geomorphic and sedimentary evidence

The reconstruction of former dam breaks dependsstrongly on the correct interpretation of the geomorphicand sedimentological record within palaeohydraulic andtopographic constraints (Clarke et al., 2004). Diagnosticsediment-landform assemblages are commonly containedin qualitative models (Maizels, 1997; Hewitt, 1998; Carlinget al., 2002; Carrivick et al., 2004a). The sediment-landform assemblages pertinent to the largest floodsknown in mountainous terrain are those on Pleistoceneice-dam break deposits in the headwaters of the Ob andYenisei Rivers, Siberian Altai (Baker et al., 1993; Carlinget al., 2002; Rudoy, 2002; Herget, 2005). There, keydepositional features comprise km-scale flood gravel bars;

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–34223414

large gravel and sand dunes with megaripples. Giant barsare typically 101–102 m thick, with occasional traces ofsurficial kettle holes from melt-out of stranded ice blocks,and had blocked major tributary channels and formedlakes before having been re-incised (Fig. 6). Exposures ofrhythmitic bedding thinning up-tributary with intercalatedfluvial, lacustrine, and slackwater deposits match some ofthe descriptions of outburst flow sediments in the PeshawarBasin, Pakistan (Cornwell, 1998). Similar, though smaller,depositional landforms than those in the Altai have alsobeen reported from prehistoric events elsewhere (Clagueand Evans, 1994; Margerison et al., 2005). Shroder Jr.(1998) described megaripples with wavelengths of �102 mand amplitudes of up to 6m, downstream of the Hattu Pirrockslide dam, Indus River, Pakistan, augmenting evidenceof catastrophic failure of numerous breached rock-ava-lanche dams along the Indus River (Hewitt, 1998).

Marren (2005) summarized key sedimentary featuresindicative of glacial lake outbursts, and highlighted theirdifferences from low-magnitude and high-frequency flowsin low-relief proglacial river systems. Diagnostic evidenceincludes, among others, breach levees; clast-supported

Fig. 7. Small fluvial hanging valley, Landwasser gorge, eastern Swiss

Alps. The trunk gorge itself has a well-developed v-shaped valley cross-

section with a maximum width of 150m at this location, indicating a

possible fluvial rejuvenation of this reach. High-magnitude outburst flows

from a major landslide-dammed lake may have outpaced rates of bedrock

incision in the tributary, thus creating this fluvial hanging valley.

boulder gravel (Cutler et al., 2002); boulder bars andimbricated terraces (Coxon et al., 1996; Cenderelli andWohl, 2003); and debris fans in areas of significant valleywidening, and directly downstream of the breached dam(Vuichard and Zimmermann, 1987; Clague and Evans,2000; Kershaw et al., 2005; Dunning et al., 2006) (Fig. 1C).These fans can attain several km2 in size and often storemost of the sediment mobilized (Clague and Evans, 2000;Schuster, 2000). Hummocky valley-floor deposits down-stream of landslide dams may also indicate outburst events(Adams, 1981), but strongly resemble glacial or mass-movement debris.The wealth of depositional features documented is in

contrast to fewer, but nevertheless impressive, landformsthat attest to the erosional efficiency of outburst flows.These include dry waterfalls, eroded bedrock canyons, andstripped bedrock surfaces (Rudoy, 2002; Carter et al.,2006). Catastrophic scour of bedrock channels duringoutburst flows may be one plausible explanation of theoccurrence of fluvial hanging tributary valleys along largebedrock gorges (Fig. 7). Finally, off-site sediment sinkssuch as fjords, lakes, and large alluvial fans, host potentialfor preserving records of outburst flows (Cowan et al.,1997; Saula et al., 2002; Benn et al., 2006). For example,coarse sandy layers in lacustrine sediments of LakeConstance temporally coincide with the proposed earlyHolocene failure of the giant (4109 m3) Flims and Taminsrock slides in the Upper Rhine valley, Swiss Alps. Thelayers were thus interpreted as evidence of two largeoutburst events from these dams (Schneider et al., 2004).Despite their pervasiveness, many landform-sedimentassemblages have not been dated. Use of palaeomagnetics,U/Th-dating, and tephrochronology has demonstrated thatdepositional megalandforms from glacial outbursts in thePacific Northwest of the United States have graduallyaccumulated on top of each other rather than having beenformed during a single event, and that some of the oldestevents date to the Plio-/Pleistocene boundary (Clagueet al., 2003a).

4. Discussion: the geomorphic relevance of natural dam

failures

4.1. Fluvial response, sediment budgets, and Quaternary

landscape evolution

The literature on natural dams in mountainous terrainleads us to deduce some important observations on theirgeomorphic imprint on mountain rivers. In contrast toproglacial outwash plains subject to constant reworking,the confinement of mountain valleys can preserve remnantsof high-level depositional surfaces from outburst flows, ifsubsequent normal flows have limited reworking potential.A key question is therefore to what extent catastrophicfailures of natural dams control landforms and processeson valley floors in high mountainous terrain.

ARTICLE IN PRESS

Fig. 8. First-order estimates of sediment yields specified for catchment

areas upstream of large rock-slide dams throughout the world. Upstream

yields were calculated from the volume of backwater fill impounded by the

dams (uncorrected for compaction effects), and averaged over the time

since dam formation. Downstream yields are mainly based on material

eroded from the dams.

O. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–3422 3415

Ice, moraine, and landslide dams contribute to regulat-ing sediment flux in mountain rivers in two opposing ways.Initially, damming imposes transport limitation and adistinct local base-level control onto the surface meltwaterdrainage or river system, trapping incoming sediment inalluvial backwater flats and prograding deltas (Fig. 1B).Repeated Pleistocene ice damming of valleys in the westernFrench Alps, for example, has forced the formation of fillterraces up to 450m thick. These were re-incised duringinterglacials, causing rivers to adjust throughout theHolocene (Brocard et al., 2003). Hewitt (1998) found thatup to 20 km3 of sediment was deposited upstream of largeindividual, and partly breached, late Quaternary rock-avalanche dams in the upper Indus River, KarakoramHimalayas, despite long-term fluvial bedrock incision ratesof 2–12mm=yr (Burbank et al., 1996). Assuming fulltrapping efficiency, such sediment wedges can be used toconstrain the mean upstream specific yield, given that theage of dam formation and the termination of infill areknown (Fig. 8). The sediment retaining effects of ice damsare largely unexplored, especially with regard to englacialdebris content and its transport in meltwater conduits.

In turn, during and immediately after dam failure, largeamounts of sediment are released together with theescaping water masses. Such failures rarely cause completeerosion of the dam or full emptying of lakes. Sedimentvolumes mobilized during historical moraine-dam failuresare of the order of 104–106 m3, thus matching the size ofhistoric outburst events in the Arctic (Magilligan et al.,2002); Pleistocene events could have transported as muchas 108 m3 (Blair, 2002) (Fig. 8). In terms of peak discharge,released water and sediment volume, historic events are oneto two orders of magnitude below that of their Pleistocenecounterparts (Table 2). Sediment discharge from landslide-dam breaks are of a comparable order of magnitude; whileexceeding mean historic basin sediment yields, they alsodecline rapidly (Walder and Driedger, 1994; Korup et al.,2004). The highest rates come from tectonically active andhumid mountain belts such as Alaska, the New ZealandSouthern Alps, and Taiwan (Fig. 8). This is exemplified bythe extreme sediment discharges from the Tsaoling andJiufengershan rock avalanches triggered by the 1999 Chi-Chi earthquake (Mw ¼ 7:6), Taiwan. Between 1.1 and1:8� 105 m3=km2=yr were delivered downstream fromthese landslides within the first years following failure(Fig. 8) (Chen et al., 2005; Chang et al., 2006).

Such elevated sediment yields cause extensive channeland floodplain aggradation during transit of bed-loadsediment waves (Sutherland et al., 2002; Clague et al.,2003b; Korup et al., 2004). Brummer and Montgomery(2006) showed that coarse lag deposits may significantlydelay sediment pulse dispersion following initial breach.This requires the coupling of numerical dam-break modelswith transport equations for quantifying the entrainmentof bi-modal particle size populations commonly found inlandslide dams (Cencetti et al., 2006). Prolonged channelinstability increases flood frequency at locations of reduced

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–34223416

channel and reservoir capacity, and channel avulsions(Clague et al., 2003b; Korup et al., 2004). Excess sedimentcan also cause cascading, i.e. multiple occurrences of, damformation and failure along a river reach within short timesafter the initial event (Clague and Evans, 2000; Hermannset al., 2004b). Riparian slope instability occurs in placeswhere flow scouring or aggradation causes undercutting orallows river channels to attack hillslope portions that werepreviously protected from fluvial erosion (Vuichard andZimmermann, 1987; Clague and Evans, 2000; Cenderelliand Wohl, 2001; Korup et al., 2004).

Quantifying the contribution of such sediment pulses tolonger-term catchment sediment budgets is often proble-matic, mainly because of limited data on their recurrence,but also the unknown extent of input from upstreamsediment (Wasson, 2003; Korup et al., 2004). Clastangularity may be one indicator of deposits derived fromlandslide-dam breaks (Saula et al., 2002), although Suther-land et al. (2002) noted from field measurements thatabrasion of weathered and fractured landslide-dam debriswas roughly an order of magnitude greater than that of theambient river gravel. In a study on the 1914 Rio Barrancas

Fig. 9. (A) Several tens of metres thick fragmented deposits of giant

(5� 109 m3) rockslide near Braga, Marsyandi valley, Central Nepal,

capped by fluvioglacial gravel, indicates preservation of formerly river-

blocking debris despite glacial re-advance. (B) Moraine-dammed lake of

Gangapurna glacier, located in the same valley; laterofrontal moraines

partly block Marsyandi River. Photographs courtesy of J.T. Weidinger.

rock avalanche-dam failure, Hermanns et al. (2004a) foundthat rounding was less pronounced in catastrophic out-burst flow deposits, suggesting that mineralogic analysiswould most reliably indicate sediment provenance.Despite these limitations, the pervasive preservation of

geomorphic evidence over 103-yr timescales has led to theproposition that exceptionally large events perform most ofthe geomorphic work within a flood series (Baker et al.,1993). Clague and Evans (2000) noted that it may take101–104 yr for mountain rivers to re-attain pre-outburstconditions, mainly because of the translation and diffusionof sediment waves, and the inability of lesser flows toobliterate all geomorphic evidence (Hewitt, 1998, 2002).Indeed, the impact of Holocene events can be preservedeven in tectonically active mountain belts where rates ofuplift and erosion are high (Fig. 9A). Pratt-Sitaula et al.(2004) described a debris-flow terrace 70–120m high alonga 35-km reach of Marsyandi River, Central NepalHimalaya, which they linked to a catastrophic outburstevent involving �1:5 km3 of debris from the HighHimalayas at 4.8 k yr. Fluvial bedrock incision ratesestimated from cosmogenic radionuclides are up to 7mm/yr on timescales of 104 yr, and highlight the persistence oflandforms created by such extreme events. A similar-sized,though only 500-yr old, debris-flow deposit impoundingPhewa Tal (¼ Lake), Pokhara, in the nearby Seti Kholabasin (Fort, 1987), shows that massive outburst events arenot restricted to the Pleistocene. Barnard et al. (2006)described several late Pleistocene hyperconcentrated- anddebris-flow fans in the Khumbu Himal, Nepal, whichformed during what are interpreted as phases of paraglacialresponse to glacial stages. These prominent fans mayindicate the dominance of catastrophic outburst-flowdeposits from glacier-dam failures in this high alpinelandscape. Most of the studies reviewed suggest thatcatastrophic dam-breaks in mountainous terrain are chieflyevents of valley-floor sediment reworking. Failures ofmoraine dams in particular cause substantial channel-floorwidening of alpine headwater reaches (Figs. 10 and 11).Conversely, there is little evidence of bedrock erosion(Fig. 12).

4.2. Inferring climatic and tectonic forcing from the

morphostratigraphic record

The preservation potential of sediments and landforms isa key constraint on reconstructing unrecorded outburstevents, especially as larger events may have obliterated orremoved evidence of previous smaller ones (Lewin andMacklin, 2003). As this is a generic problem in Quaternarygeo(morpho)logy, complete records of outburst events relyon their unequivocal identification. Even today, causes andeffects of natural dam failures in inaccessible mountainousterrain may be misinterpreted in the absence of detailedinvestigations (Adhikari and Koshimizu, 2005). Cata-strophic dam breaks are often invoked as explanations forconspicuous facies or anomalies in the morphostratigraphic

ARTICLE IN PRESS

Fig. 10. (A) LANDSAT ETM+ subscene (30 October 2000; path 140, row 041, RGB 421) of GLOF track from the 1998 Sabai Tsho moraine-dam failure

below Tam Pokhari Glacier, affecting �2:2 km2, Hinku Khola, Khumbu Himal, Nepal. (B) Active channel width measured from ETM+ band 8 at 15-m

resolution; hatched line is mean. Image courtesy of Global Land Cover Facility, University of Maryland.

Fig. 11. Long-profiles of three historic GLOFs, Khumbu Himal, Nepal. Histogram shows regional distribution of n ¼ 62 glacial lakes of area40:05 km2

with elevation, mapped from satellite image taken in October 2000 (Fig. 10). Horizontal black line and hatched lines are mean and standard deviations,

respectively. Note how GLOFs initiated from lakes at lower altitudes; also note rectilinear channel profiles with similar gradients.

O. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–3422 3417

record (Martin and Turner, 1998; Bergossi and DellaFavera, 2002; Saula et al., 2002). However, severalsimilarities in the geomorphic and sedimentary recorddescribed above do complicate inferences on the types ofnatural dams that gave rise to such flows. Evidence may not

always allow a reliable distinction between failures ofglacier and landslide dams, even when remnants of formerdams prevail (Hewitt, 1999). Hence interpretations ofoutburst deposits may erroneously invoke the necessityof glacier presence together with all of the underlying

ARTICLE IN PRESS

Fig. 12. Cartoon summarizing key sediment-landform assemblages of ice, moraine, and landslide dams in mountainous terrain. Given above are

characteristic timescales over which geomorphic evidence of these dams persists. Typical impacts comprise reach-scale base-level control driving pulsed

aggradation and downstream diffusion of sediments on 100–104�yr timescales.

O. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–34223418

palaeoclimatic implications, where a single landslide-damfailure could have produced a similar result in thesedimentary record. This especially applies to high moun-tain catchments prone to both strong glacier dynamics andfrequent slope failure. There, ambiguous morphostratigra-phy may lead to the mistaking of comminuted rockslide/rock-avalanche debris for glacial moraines (Orombelli andPorter, 1988; Hewitt, 1999). We also note that surprisinglyfew studies have explicitly addressed the possibility ofmultiple or polygenetic dams in formerly glaciatedterrain (Krivonogov et al., 2005). For example, morainedams in actively deglaciating headwaters subject may bereadily re-shaped or buried by landslides from unstablehillslopes. In contrast, several of the larger landslidedams in the European Alps or the Himalayas sustainerratic boulders or fluvioglacial gravel indicating glacialre-advances across formerly valley-blocking deposits(Weidinger, 2006) (Fig. 9A).

4.3. Looking ahead—possible effects of climate change

Mountain environments are particularly prone tochanges in environmental boundary conditions, andclimate change will have implications for the formationof natural dams (Evans and Clague, 1994). Changes intemperature, precipitation, and sediment flux affect themass balance of mountain glaciers, and Richardson andReynolds (2000) made the point that the number ofmoraine-dammed lakes is increasing in the Himalayas withrecent climate warming (Fig. 11). Similarly, glacial lakes insouthern Tibet have gained both in number and total areaduring the last 20 years (Chen et al., 2007), while thedevelopment of thermokarst has been observed (Haeberliet al., 2001). However, the melting of glaciers not onlysignifies the potential for the development of moraine-dammed lakes (Clague and Evans, 2000); it also promotesparaglacial slope adjustment, especially where debrisbodies and rock walls lose internal cohesion throughmelting ice cores and degrading permafrost. In the

Khumbu Himal, Nepal, Fukui et al. (2007) noted a riseof the permafrost lower limit of 100–300m over the lastthree decades. Maintained negative mass balances con-tribute to more frequent ice fall and avalanches fromhanging glaciers, raising the potential for catastrophicdisplacement waves in glacial lakes (Hubbard et al., 2005;Vilimek et al., 2005; Harrison et al., 2006). A corollary ofthis is that geomorphic legacies of ice- and moraine-dambreaks should be most prominent in alpine headwaterssubject to dynamic glacial fluctuations (Barnard et al.,2006), whereas impacts related to climate-driven landslidedams can be more randomly distributed within a givencatchment (Hewitt, 2002).

5. Conclusions and recommendations for future research

Despite a large body of literature on the geomorphic andsedimentary consequences of outburst flows on proglacialoutwash plains or moderate relief in high-latitude regions,comparable work on confined mountain valleys is rare.This is rather striking, given the frequent historicoccurrence of ice, moraine and landslide-dam failures inmountain belts throughout the world.Data on the geometry and processes of moraine and

landslide dams are becoming increasingly available in theform of regional inventories. Yet there are crucial short-comings with respect to reliably pin-pointing key para-meters of dam stability, outburst flow magnitude, andgeomorphic process response. Recent studies have shownthe need to better understand, and possibly predict, thetemporal and spatial variation of flow discharge, single-and multiple-wave attenuation and routing, sedimenttransport, and residence time.Although geomorphic and sedimentary evidence of

catastrophic outburst flows persists even in mountain beltssubject to high erosion rates, unequivocal reconstruction ofthe causes of damming and failure is not alwaysstraightforward. This particularly applies to high-moun-tain belts with ample potential for the formation and

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–3422 3419

failure of ice, moraine, landslide, or polygenetic dams.Inferring the existence of a former glacial dam and all itspalaeoclimatic implications, where a landslide dam couldhave been equally responsible for the suite of landformsand sediments observed, may lead to considerable mis-interpretation of Quaternary landscape dynamics and theunderlying climatic or tectonic forcing.

Climate warming will have overall negative implicationson glacier mass balance and the number of moraine-dammed lakes is likely to further increase. Likewise, rock-slope stability may deteriorate due to loss of cohesion inthe wake of high-mountain permafrost degradation. Thepossible effects of climate warming on the formation,stability, and failure of landslide dams, however, remainless clear. This is especially the case in tectonically activemountain belts, where frequent earthquakes may be anequally important trigger of natural dam formation andfailure.

The findings of our review lead us to recommend thefollowing future research directions:

�

Investigation of systematic patterns of climate changeand earthquake disturbance as key controls on theformation, failure, and distribution of ice, moraine, andlandslide dams, including methods to better interpretevidence of dam failures with regard to the initial type ofdam. � Quantification of response of mountain rivers to

catastrophic outburst events and their concomitantprocess sequences.

� Elaboration of a comprehensive classification of natural

dams in mountainous terrain with special attention topolygenetic dams.

� Physical-based modelling of dam formation, failure, and

routing of water and sediment outbursts.

� Identification of quantitative controls on the contribu-

tion of natural dams to sediment budgets in mountai-nous terrain.

Acknowledgements

We thank Robin McKillop and John Clague for sharingunpublished data, and two anonymous reviewers for theirhelpful comments. OK acknowledges support by EU-FP6Grant no. 081412 (‘‘IRASMOS’’). FST thanks SarahVerleysdonk for collating some of the literature for thisreview.

References

Adams, J.E., 1981. Earthquake-dammed lakes in New Zealand. Geology

9, 215–219.

Adhikari, D.P., Koshimizu, S., 2005. Debris flow disaster at Larcha, upper

Bhotekoshi Valley, central Nepal. Island Arc 14, 410–423.

Aizen, V.B., Aizen, E.M., Melack, J.M., Dozier, J., 1997. Climatic and

hydrologic changes in the Tien Shan, Central Asia. Journal of Climate

10, 1393–1404.

Alley, R.B., Agustsdottir, A.M., 2005. The 8k event: cause and

consequences of a major Holocene abrupt climate change. Quaternary

Science Reviews 24, 1123–1149.

Anderson, S.P., Fernald, K.M.H., Anderson, R.S., Humphrey, N.F.,

1999. Physical and chemical characterization of a spring flood event,

Bench Glacier, Alaska, USA: evidence for water storage. Journal of

Glaciology 45, 177–189.

Anderson, S.P., Walder, J.S., Anderson, R.S., Kraal, E.R., Cunico, M.,

Fountain, A.G., Trabant, D.C., 2003. Integrated hydrologic and

hydrochemical observations of Hidden Creek Lake jokulhlaups,

Kennicott Glacier, Alaska. Journal of Geophysical Research–Earth

Surface 108.

Andrews, J.T., Dunhill, G., 2004. Early to mid-Holocene Atlantic water

influx and deglacial meltwater events, Beaufort Sea slope, Arctic

Ocean. Quaternary Research 61, 14–21.

Baker, V.R., Bunker, R.C., 1985. Cataclysmic late pleistocene flooding

from glacial lake missoula: a review. Quaternary Science Reviews 4,

1–41.

Baker, V.R., Benito, G., Rudoy, A.N., 1993. Paleohydrology of late

pleistocene superflooding, Altay Mountains, Siberia. Science 259,

348–350.

Barnard, P.L., Owen, L.A., Finkel, R.C., 2006. Quaternary fans and

terraces in the Khumbu Himal south of Mount Everest: their

characteristics, age and formation. Journal of the Geological Society

163, 383–399.

Batalla, R.J., De Jong, 1999. Field observations on hyperconcentrated

flows in mountain torrents. Earth Surface Processes and Landforms

24, 247–253.

Benito, G., 1997. Energy expenditure and geomorphic work of the

cataclysmic Missoula flooding in the Columbia River gorge, USA.

Earth Surface Processes and Landforms 22, 457–472.

Benn, D.I., Owen, L.A., 2002. Himalayan glacial sedimentary environ-

ments: a framework for reconstructing and dating the former extent of

glaciers in high mountains. Quaternary International 97–98, 3–25.

Benn, D.I., Owen, L.A., Finkel, R.C., Clemmens, S., 2006. Pleistocene

lake outburst floods and fan formation along the eastern Sierra

Nevada, California: implications for the interpretation of intermon-

tane lacustrine records. Quaternary Science Reviews 25, 2729–2748.

Bergossi, R., Della Favera, J.C., 2002. Catastrophic floods as possible

cause of organic matter accumulation giving rise to coal formation,

Parana, Brazil. International Journal of Coal Geology 52, 83–89.

Bjornsson, H., 2003. Subglacial lakes and jokulhlaups in Iceland. Global

and Planetary Change 35, 255–271.

Bjornsson, H., 2004. Glacial lake outburst floods in mountain environ-

ments. In: Owens, P.N., Slaymaker, O. (Eds.), Mountain Geomor-

phology. Hodder & Stoughton, London, pp. 155–184.

Blair, T.C., 2002. Alluvial-fan sedimentation from a glacial-outburst

flood, Lone Pine, California, and contrasts with meteorological flood

deposits. In: Martini, P., Baker, V., Garzon, G. (Eds.), Flood and

Megaflood Processes and Deposits: Recent and Ancient Examples.

Special Publication International Association of Sedimentologists, vol.

32. Blackwell, Oxford, pp. 113–140.

Blais-Stevens, A., Clague, J.J., Mathewes, R.W., Hebda, R.J., Bornhold,

B.D., 2003. Record of large, Late Pleistocene outburst floods preserved

in Saanich Inlet sediments, Vancouver Island, Canada. Quaternary

Science Reviews 22, 2327–2334.

Brocard, G.Y., van der Beek, P.A., Bourles, D.L., Siame, L.L., Mugnier,

J.L., 2003. Long-term fluvial incision and postglacial river relaxation

time in the French Western Alps from 10Be dating of alluvial terraces

with assessment of inheritance, soil development and wind ablation

effects. Earth and Planetary Science Letters 209, 197–214.

Brummer, C.J., Montgomery, D.R., 2006. Influence of coarse lag

formation on the mechanics of sediment pulse dispersion in a

mountain stream, Squire Creek, North Cascades, Washington, United

States. Water Resources Research 42, W07412, doi:10.1029/

2005WR004776.

Burbank, D.W., Leland, J., Fielding, E., Anderson, R.S., Brozovic, N.,

Reid, M.R., Duncan, C., 1996. Bedrock incision, rock uplift and

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–34223420

threshold hillslopes in the northwestern Himalayas. Nature 379,

505–510.

Capart, H., Young, D.-L., Zech, Y., 2001. Dam-break induced debris

flow. In: McCaffrey, W., Kneller, B., Peakall, J. (Eds.), Particle

Gravity Currents. Special Publication International Association of

Sedimentologists, vol. 31. Blackwell, Oxford, pp. 149–156.

Carling, P.A., Kirkbride, A.D., Parnachov, S., Borodavko, P.S.,

Berger, G.W., 2002. Late quaternary catastrophic flooding

in the Altai Mountains of south-central Siberia: a synoptic

overview and an introduction to flood deposit sedimentology.

In: Martini, P., Baker, V., Garon, G. (Eds.), Flood and

Megaflood Processes and Deposits, vol. 32. Blackwell, Oxford,

pp. 17–35.

Carrivick, J.L., Russell, A.J., Tweed, F.S., 2004a. Geomorphological

evidence for jokulhlaups from Kverkfjoll volcano, Iceland. Geomor-

phology 63, 81–102.

Carrivick, J.L., Russell, A.J., Tweed, F.S., Twigg, D., 2004b. Palaeohy-

drology and sedimentary impacts of jokulhlaups from Kverkfjoll

Iceland. Sedimentary Geology 172, 19–40.

Carter, D.T., Ely, L.L., O’Connor, J.E., Fenton, C.R., 2006. Late

Pleistocene outburst flooding from pluvial Lake Alvord into the

Owyhee River, Oregon. Geomorphology 75, 346–367.

Casagli, N., Ermini, L., Rosati, G., 2003. Determining grain size

distribution of the material composing landslide dams in the northern

Apennines: sampling and processing methods. Engineering Geology

69, 83–97.

Cencetti, C., Fredduzzi, A., Marchesini, I., Naccini, M., Tacconi, P., 2006.

Some considerations about the simulation of breach channel erosion

on landslide dams. Computational Geosciences 10, 201–219.

Cenderelli, D.A., 2000. Floods from natural and artificial dam failures. In:

Wohl, E. (Ed.), Inland Flood Hazards. Cambridge University Press,

New York, pp. 73–103.

Cenderelli, D.A., Wohl, E.E., 2001. Peak discharge estimates of glacial-

lake outburst floods and ‘‘normal’’ climatic floods in the Mount

Everest region, Nepal. Geomorphology 40, 57–90.

Cenderelli, D.A., Wohl, E.E., 2003. Flow hydraulics and geomorphic

effects of glacial-lake outburst floods in the Mount Everest region,

Nepal. Earth Surface Processes and Landforms 28, 385–407.

Chai, H.J., Liu, H.C., Zhang, Z.Y., Xu, Z.W., 2000. The distribution,

causes and effects of damming landslides in China. Journal of

Chengdu University of Technology 27, 302–307.

Chang, K.J., Taboada, A., Chan, Y.C., Dominguez, S., 2006. Post-seismic

surface processes in the Jiufengershan landslide area, 1999 Chi-Chi

earthquake epicentral zone, Taiwan. Engineering Geology 86,

102–117.

Chapman, M.G., Gudmundsson, M.T., Russell, A.J., Hare, T.M., 2003.

Possible Juventae Chasma subice volcanic eruptions and Maja Valles

ice outburst floods on Mars: implications of Mars Global Surveyor

crater densities, geomorphology, and topography. Journal of

Geophysical Research–Planets 108 E10, 5113, doi:10.1029/

2002JE002009.

Chen, C.Y., Chen, T.C., Yu, F.C., Hung, F.Y., 2004. A landslide dam

breach induced debris flow—a case study on downstream hazard areas

delineation. Environmental Geology 47, 91–101.

Chen, R.F., Chan, Y.C., Angelier, J., Hu, J.C., Huang, C., Chang, K.J.,

Shih, T.Y., 2005. Large earthquake-triggered landslides and mountain

belt erosion: the Tsaoling case, Taiwan. Comptes Rendues Geoscience

337, 1164–1172.

Chen, X., Cui, P., Li, Y., Yang, Z., Qi, Y., 2007. Changes in glacial lakes

and glaciers of post-1986 in the Poiqu River basin, Nyalam, Xizang

(Tibet). Geomorphology 86, 298–311.

Chigira, M., Wang, W.N., Furuya, T., Kamai, T., 2003. Geological causes

and geomorphological precursors of the Tsaoling landslide triggered

by the 1999, Chi-Chi earthquake Taiwan. Engineering Geology 68,

259–273.

Clague, J.J., Evans, S.G., 1994. Formation and failure of natural dams in

the Canadian Cordillera. Geological Survey of Canada Bulletin 464,

35pp.

Clague, J.J., Evans, S.C., 2000. A review of catastrophic drainage of

moraine-dammed lakes in British Columbia. Quaternary Science

Reviews 19, 1763–1783.

Clague, J.J., Barendregt, R., Enkin, R.J., Foit, F.F., 2003a. Paleomagnetic

and tephra evidence for tens of Missoula floods in southern

Washington. Geology 31, 247–250.

Clague, J.J., Turner, R.J.W., Reyes, A.V., 2003b. Record of recent river

channel instability Cheakamus Valley, British Columbia. Geomor-

phology 53, 317–322.

Clarke, G.K.C., Leverington, D.W., Teller, J.T., Dyke, A.S., 2004.

Paleohydraulics of the last outburst flood from glacial Lake Agassiz

and the 8200 BP cold event. Quaternary Science Reviews 23,

389–407.

Cornwell, K., 1998. Quaternary break-out flood sediments in the

Peshawar basin of northern Pakistan. Geomorphology 25, 225–248.

Costa, J.E., Schuster, R.L., 1988. The formation and failure of natural

dams. Geological Society of America Bulletin 100, 1054–1068.

Costa, J.E., Schuster, R.L., 1991. Documented historical landslide dams

from around the world. U.S. Geological Survey Open-File Report 91-

239, 486pp.

Cowan, E.A., Cai, J.K., Powell, R.D., Clark, J.D., Pitcher, J.N., 1997.

Temperate glacimarine varves: an example from Disenchantment

Bay, southern Alaska. Journal of Sedimentary Research 67,

536–549.

Coxon, P., Owen, L.A., Mitchell, W.A., 1996. A late Quaternary

catastrophic flood in the Lahul Himalayas. Journal of Quaternary

Science 11, 495–510.

Cutler, P.M., Colgan, P.M., Mickelson, D.M., 2002. Sedimentologic

evidence for outburst floods from the Laurentide ice sheet margin in

Wisconsin, USA: implications for tunnel-channel formation. Quatern-

ary International 90, 23–40.

Dai, F.C., Lee, C.F., Deng, J.H., Tham, L.G., 2005. The 1786 earthquake-

triggered landslide dam and subsequent dam-break flood on the Dadu

River, southwestern China. Geomorphology 65, 205–221.

Davies, T.R., McSaveney, M.J., 2002. Dynamic simulation of the motion

of fragmenting rock avalanches. Canadian Geotechnical Journal 39,

789–798.

Davies, T.R., McSaveney, M.J., Beetham, R.D., 2006. Rapid block glides:

slide-surface fragmentation in New Zealand’s Waikaremoana land-

slide. Quarterly Journal of Engineering Geology and Hydrogeology

39, 115–129.

Davies, T.R.H., Smart, C.C., Turnbull, J.M., 2003. Water and sediment

outburst floods from advanced Franz Josef Glacier, New Zealand.

Earth Surface Processes and Landforms 28, 1081–1096.

Delisle, G., Reynolds, J.M., Hanisch, J., Pokhrel, A.P., Pant, S., 2003.

Lake Thulagi/Nepal: rapid landscape evolution in reaction to climatic

change. Zeitschrift fur Geomorphologie 47, 1–9.

Ding, Y., Liu, J., 1992. Glacial lake outburst flood disasters in China.

Annals of Glaciology 16, 180–184.

Dixit, A., 2003. Floods and vulnerability: need to rethink flood manage-

ment. Natural Hazards 28, 155–179.

Dongtao, M.A., Jianjun, T.U., Peng, C.U.I., Ruren, L.U., 2004.

Approach to mountain hazards in Tibet, China. Journal of Mountain

Science 1, 143–154.

Dunning, S.A., Rosser, N.J., Petley, D.N., Massey, C.R., 2006. Formation

and failure of the Tsatichhu landslide dam, Bhutan. Landslides 3,

107–113.

Eisbacher, G.H., Clague, J.J., 1984. Destructive mass movements in high

mountains: hazard and management. Geological Survey of Canada

Paper 84–16, 230pp.

Ermini, L., Casagli, N., 2003. Prediction of the behaviour of landslide

dams using a geomorphological dimensionless index. Earth Surface

Processes and Landforms 28, 31–47.

Evans, S.G., Clague, J.J., 1994. Recent climatic change and catastrophic

geomorphic processes in mountain environments. Geomorphology 10,

107–128.

Fairen, A.G., Dohm, J.M., 2003. Episodic flood inundations of the

northern plains of Mars. Icarus 165, 53–67.

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–3422 3421

Fort, M., 1987. Sporadic morphogenesis in a continental subduction

setting: an example from the Annapurna Range, Nepal Himalaya.

Zeitschrift fur Geomorphologie Supplementband NF 63,

9–36.

Fukui, K., Fujii, Y., Ageta, Y., Asahi, K., 2007. Changes in the lower limit

of mountain permafrost between 1973 and 2004 in the Khumbu

Himal, the Nepal Himalayas. Global and Planetary Change 55,

251–256.

Geertsema, M., Clague, J.J., 2005. Jokulhlaups at Tulsequah Glacier,

northwestern British Columbia, Canada. Holocene 15, 310–316.

Haeberli, W., 1983. Frequency and characteristics of glacier floods in the

Swiss Alps. Annals of Glaciology 4, 85–90.

Haeberli, W., Kaab, A., Muhll, D.V., Teysseire, P., 2001. Prevention of

outburst floods from periglacial lakes at Grubengletscher, Valais,

Swiss Alps. Journal of Glaciology 47, 111–122.

Harrison, S., Glasser, N., Winchester, V., Haresign, E., Warren, C.,

Jansson, K., 2006. A glacial lake outburst flood associated with recent

mountain glacier retreat, Patagonian Andes. Holocene 16, 611–620.

Herget, J., 2005. Reconstruction of Pleistocene ice-dammed lake outburst

floods in the Altai Mountains, Siberia. Geological Society of America

Special Paper 386, 118pp.

Hermanns, R.L., Naumann, R., Folguera, A., Pagenkopf, A., 2004a.

Sedimentologic analyses of deposits of a historic landslide dam failure

in Barrancas valley causing the catastrophic 1914 Rio Colorado flood,

northern Patagonia, Argentina. In: Lacerda, W., Ehrlich, M.,

Fontoura, S., Sayao, A. (Eds.), Landslides: Evaluation and Stabiliza-

tion. Taylor and Francis, London, pp. 1439–1445.

Hermanns, R.L., Niedermann, S., Ivy-Ochs, S., Kubik, P.W., 2004b. Rock

avalanching into a landslide-dammed lake causing multiple dam

failure in Las Conchas valley (NW Argentina)—evidence from surface

exposure dating and stratigraphic analyses. Landslides 1, 113–122.

Herschy, R., 2002. The world’s maximum observed floods. In: Snorrason,

A., Finnsdottir, H., Moss, M. (Eds.), The Extremes of the Extremes:

Extraordinary Floods. vol. 271, IAHS Publications, pp. 355–360.

Hewitt, K., 1998. Catastrophic landslides and their effects on the upper

Indus streams, Karakoram Himalaya, northern Pakistan. Geomor-

phology 26, 47–80.

Hewitt, K., 1999. Quaternary moraines vs. catastrophic rock avalanches in

the Karakoram Himalaya, northern Pakistan. Quaternary Research

51, 220–237.

Hewitt, K., 2002. Postglacial landform and sediment associations in a

landslide-fragmented river system: the Transhimalayan Indus streams.

In: Hewitt, K., Byrne, M., English, M., Young, G. (Eds.), Landscapes

of Transition. Landform Assemblages and Transformations in Cold

Regions. Kluwer Academic Publishers, Central Asia, Dordrecht,

pp. 63–91.

Hicks, D.M., McSaveney, M.J., Chinn, T.J.H., 1990. Sedimentation in

proglacial Ivory Lake, Southern Alps, New Zealand. Arctic and Alpine

Research 22, 26–42.

Hubbard, B., Heald, A., Reynolds, J.M., Quincey, D., Richardson, S.D.,

Luyo, M.Z., Portilla, N.S., Hambrey, M.J., 2005. Impact of a rock

avalanche on a moraine-dammed proglacial lake: Laguna Safuna Alta,

Cordillera Blanca, Peru. Earth Surface Processes and Landforms 30,

1251–1264.

Jackson, L.E., 1979. Catastrophic glacial outburst flood (jokulhlaup)

mechanism for debris flow generation at the Spiral Tunnels, Kicking

Horse River basin, British Columbia. Canadian Geotechnical Journal

16, 806–813.

Kershaw, J.A., Clague, J.J., Evans, S.G., 2005. Geomorphic and

sedimentological signature of a two-phase outburst flood from

moraine-dammed Queen Bess Lake, British Columbia, Canada. Earth

Surface Processes and Landforms 30, 1–25.

Khanal, N., Chaudhury, M., Tianchi, L., 2002. Risk, vulnerability, and

sustainable development in mountain areas of Asia. in: Asia High

Summit 2002, Kathmandu, 24pp.

King, J., Loveday, I., Schuster, R.L., 1989. The 1985 Bairaman landslide

dam and resulting debris flow, Papua New Guinea. Quarterly Journal

of Engineering Geology 22, 257–270.

Korup, O., 2002. Recent research on landslide dams—a literature review

with special attention to New Zealand. Progress in Physical

Geography 26, 206–235.

Korup, O., 2004. Geomorphometric characteristics of New Zealand

landslide dams. Engineering Geology 73, 13–35.

Korup, O., McSaveney, M.J., Davies, T.R.H., 2004. Sediment generation

and delivery from large historic landslides in the Southern Alps, New

Zealand. Geomorphology 61, 189–207.

Korup, O., Strom, A.L., Weidinger, J.T., 2006. Fluvial response to large

rock-slope failures—examples from the Himalayas, the Tien Shan, and

the Southern Alps in New Zealand. Geomorphology 78, 3–21.

Krivonogov, S.K., Sheinkman, V.S., Mistruykov, A.A., 2005. Stages in

the development of the Darhad dammed lake (northern Mongolia)

during the Late Pleistocene and Holocene. Quaternary International

136, 83–94.

Lapointe, M.F., Secretan, Y., Driscoll, S.N., Bergeron, N., Leclerc, M.,

1998. Response of the Ha! Ha! River to the flood of July 1996 in the

Saguenay Region of Quebec: large-scale avulsion in a glaciated valley.

Water Resources Research 34, 2383–2392.

Larsen, S.H., Davies, T.R.H., McSaveney, M.J., 2005. A possible

coseismic landslide origin of late Holocene moraines of the Southern

Alps, New Zealand. New Zealand Journal of Geology and Geophysics

48, 311–314.

Lewin, J., Macklin, M.G., 2003. Preservation potential for late

Quaternary river alluvium. Journal of Quaternary Science 18, 107–120.

Li, M.H., Hsu, M.H., Hsieh, L.S., Teng, W.H., 2002. Inundation

potentials analysis for Tsao-Ling landslide lake formed by Chi-Chi

earthquake in Taiwan. Natural Hazards 25, 289–303.

Liu, J., 1992. Jokulhlaups in the Kunmalike River, southern Tien Shan

mountains, China. Annals of Glaciology 16, 85–88.

Lliboutry, L., Morales, B., Pautre, A., Schneider, B., 1977. Glaciological

problems set by the control of dangerous lakes in Cordillera Blanca,

Peru. I: Historical failure of morainic dams, their causes and

prevention. Journal of Glaciology 18, 239–254.

Magilligan, F.J., Gomez, B., Mertes, L.A.K., Smith, L.C., Smith, N.D.,

Finnegan, D., Garvin, J.B., 2002. Geomorphic effectiveness, sandur

development, and the pattern of landscape response during jokulhlaups:

Skeidararsandur, southeastern Iceland. Geomorphology 44, 95–113.

Maizels, J., 1997. Jokulhlaup deposits in proglacial areas. Quaternary

Science Reviews 16, 793–819.

Margerison, H.R., Phillips, W.M., Stuart, F.M., Sugden, D.E., 2005.

Cosmogenic 3He concentrations in ancient flood deposits from the

Coombs Hills, northern Dry Valleys, East Antarctica: interpreting

exposure ages and erosion rates. Earth and Planetary Science Letters

230, 163–175.

Marren, P.M., 2002. Criteria for distinguishing high magnitude flood

events in the proglacial sedimentary record. in: Snorrason, A.,

Finnsdottir, H., Moss, M. (Eds.), The Extremes of the Extremes:

Extraordinary Floods, IAHS Publications, vol. 271, pp. 237–242.

Marren, P.M., 2005. Magnitude and frequency in proglacial rivers: a

geomorphological and sedimentological perspective. Earth-Science

Reviews 70, 203–251.

Martin, C.A.L., Turner, B.R., 1998. Origins of massive-type sandstone in

braided river systems. Earth Science Reviews 44, 15–38.

Martini, P.I., Baker, V.R., Garzon, G., 2002. Flood and Megaflood

Processes and Deposits: Recent and Ancient Examples. Special

Publication International Association of Sedimentologists, vol. 32.

Blackwell, Oxford.

Mayo, L.R., 1989. Advances of Hubbard Glacier and the 1986 outburst of

Russell Fjord, Alaska, USA. Annals of Glaciology 13, 189–194.

McKillop, R.J., Clague, J.J., 2007. Statistical, remote sensing-based

approach for estimating the probability of catastrophic drainage from

moraine-dammed lakes in southwestern British Columbia. Global and

Planetary Change 56, 153–171.

Montgomery, D.R., Hallet, B., Yuping, L., Finnegan, N., Anders, A.,

Gillespie, A., Greenberg, H.M., 2004. Evidence for Holocene

megafloods down the Tsangpo River gorge, southeastern Tibet.

Quaternary Research 62, 201–207.

ARTICLE IN PRESSO. Korup, F. Tweed / Quaternary Science Reviews 26 (2007) 3406–34223422

Mool, P.K., 1995. Glacier lake outburst floods in Nepal. Journal of Nepal

Geological Society 11, 273–280.

Ng, F., Bjornsson, H., 2003. On the Clague–Mathews relation for

jokulhlaups. Journal of Glaciology 49, 161–172.

O’Connor, J.E., Costa, J.E., 2004. The world’s largest floods, past and

present—their causes and magnitudes. U.S. Geological Survey

Circular 1254, 13pp.

O’Connor, J.E., Hardison I, J.H., Costa, J.E., 2001. Debris flows from

failures of Neoglacial-age moraines in the Three Sisters and Mount

Jefferson Wilderness Areas, Oregon. U.S. Geological Survey Profes-

sional Paper 1606.

Orombelli, G., Porter, S.C., 1988. Boulder deposit of upper Val Ferret

(Courmayeur Aosta valley): deposit of a historic giant rockfall and

debris avalanche or a late-glacial moraine? Eclogae Geologicae

Helveticae 81, 365–371.

Pratt-Sitaula, B., Burbank, D.W., Heimsath, A., Ojha, T., 2004. Land-

scape disequilibrium on 1000–10,000 year scales, Marsyandi River,

Nepal, central Himalaya. Geomorphology 58, 223–241.

Pushkarenko, V.P., Nikitin, A.M., 1988. Experience in the regional

investigation of the state of mountain lake dams in Central Asia and

the character of breach mudflow formation. In: Kozlovskii, E. (Ed.),

Landslides and Mudflows. UNEP/UNESCO, Moscow, pp. 359–362.

Quincey, D.J., Richardson, S.D., Luckman, A., Lucas, R.M., Reynolds,

J.M., Hambrey, M.J., Glasser, N.F., 2007. Early recognition of glacial

lake hazards in the Himalaya using remote sensing datasets. Global

and Planetary Change 56, 137–152.

Raymond, M., Wegmann, M., Funk, M., 2003. Inventory of glacial

hazards in Switzerland. Mitteilungen der Versuchsanstalt fur Wasser-

bau Hydrologie und Glaziologie ETH Zurich 182, 368pp.

Richardson, S.D., Reynolds, J.M., 2000. An overview of glacial hazards in

the Himalayas. Quaternary International 65/66, 31–47.

Risley, J.C., Walder, J.S., Denlinger, R.P., 2006. Usoi dam wave

overtopping and flood routing in the Bartang and Panj Rivers,

Tajikistan. Natural Hazards 38, 375–390.

Roberts, M.J., 2005. Jokulhlaups: a reassessment of floodwater flow

through glaciers. Reviews of Geophysics 43.

Roberts, M.J., Russell, A.J., Tweed, F.S., Knudsen, O., 2001. Controls on

englacial sediment deposition during the November 1996 jokulhlaup,

Skeidararjokull, Iceland. Earth Surface Processes and Landforms 26,

935–952.

Rudoy, A.N., 2002. Glacier-dammed lakes and geological work of glacial

superfloods in the Late Pleistocene, southern Siberia, Altai Mountains.

Quaternary International 87, 119–140.

Saula, E., Emili Mato, E., Puigdefabregas, C., 2002. Catastrophic debris-

flow deposits from an inferred landslide-dam failure, Eocene Berga

Formation, eastern Pyrenees, Spain. In: Martini, P., Baker, V.,

Garzon, G. (Eds.), Flood and Megaflood Processes and Deposits:

Recent and Ancient Examples. Special Publication International

Association of Sedimentologists. Blackwell, Oxford, pp. 195–209.

Schneider, J.L., Pollet, N., Chapron, E., Wessels, M., Wassmer, P., 2004.

Signature of Rhine valley sturzstrom dam failures in Holocene

sediments of Lake Constance, Germany. Sedimentary Geology 169,

75–91.

Schuster, R.L., 2000. Outburst debris flows from failure of natural

dams. In: Wieczorek, G., Naeser, N. (Eds.), Second International

Conference on Debris-Flow Hazard Mitigation. Balkema, Taipeh,

Taiwan, pp. 29–42.

Schuster, R.L., Alford, D., 2004. Usoi landslide dam and Lake Sarez,

Pamir Mountains, Tajikistan. Environmental and Engineering

Geoscience 10, 151–168.

Shang, Y.J., Yang, Z.F., Li, L.H., Liu, D., Liao, Q.L., Wang, Y.C., 2003.

A super-large landslide in Tibet in 2000: background, occurrence,

disaster, and origin. Geomorphology 54, 225–243.

Shresta, M.L., Shresta, A.B., 2004. Recent trends and potential climatic

change impacts on glacier retreat/glacier lakes in Nepal and potential

adaptation measures. In: OECD Global Forum on Sustainable

Development, Paris, France, 21pp.

Shroder Jr., J.F., 1998. Slope failure and denudation in the western

Himalaya. Geomorphology 26, 81–105.

Smith, G.A., 1993. Missoula flood dynamics and magnitudes inferred

from sedimentology of slack-water deposits on the Columbia Plateau,

Washington. Geological Society of America Bulletin 105, 77–100.

Snorrason, A., Finnsdottir, H.P., Moss, M.E., 2002. The Extremes of the

Extremes: Extraordinary Floods. IAHS Publications, vol. 271.

Sutherland, D.G., Ball, M.H., Hilton, S.J., Lisle, T.E., 2002. Evolution of

a landslide-induced sediment wave in the Navarro River, California.

Geological Society of America Bulletin 114, 1036–1048.

Thorarinsson, S., 1939. The ice-dammed lakes of Iceland, with particular

reference to their values as indicators of glacier oscillations.

Geografiska Annaler 21, 216–242.

Tomasson, H., 2002. Catastrophic floods in Iceland. in: Snorrason, A.,

Finnsdottir, H., Moss, M. (Eds.), The Extremes of the Extremes:

Extraordinary Floods. IAHS Publications, vol. 271, pp. 121–126.

Tweed, F.S., 2000. Jokulhlaup initiation by ice-dam flotation: the

significance of glacier debris content. Earth Surface Processes and

Landforms 25, 105–108.

Tweed, F.S., Russell, A.J., 1999. Controls on the formation and sudden

drainage of glacier-impounded lakes: implications for jokulhlaup

characteristics. Progress in Physical Geography 23, 79–110.

Vilimek, V., Zapata, M.L., Klimes, J., Patzelt, Z., Santillan, N., 2005.

Influence of glacial retreat on natural hazards of the Palcacocha Lake

area, Peru. Landslides 2, 107–115.

Vuichard, D., Zimmermann, M., 1987. The 1985 catastrophic drainage of

a moraine-dammed lake, Khumbu Himal, Nepal: causes and

consequences. Mountain Research and Development 7, 91–110.

Walder, J.S., Costa, J.E., 1996. Outburst floods from glacier-dammed

lakes: the effect of mode of lake drainage on flood magnitude. Earth

Surface Processes and Landforms 21, 701–723.

Walder, J.S., Driedger, C.L., 1994. Rapid geomorphic change caused by

glacial outburst floods and debris flows along Tahoma Creek, Mount

Rainier, Washington, USA. Arctic and Alpine Research 26, 319–327.

Walder, J.S., O’Connor, J.E., 1997. Methods for predicting peak discharge

of floods caused by failure of natural and constructed earthen dams.

Water Resources Research 33, 2337–2348.

Walder, J.S., Trabant, D.C., Cunico, M., Fountain, A.G., Anderson, S.P.,

Anderson, R.S., Malm, A., 2006. Local response of a glacier to annual

filling and drainage of an ice-dammed lake. Journal of Glaciology 52,

440–450.

Warburton, J., Fenn, C.R., 1994. Unusual flood events from an alpine

glacier—observations and deductions on generating mechanisms.

Journal of Glaciology 40, 176–186.

Warren, C., Aniya, M., 1999. The calving glaciers of southern South

America. Global and Planetary Change 22, 59–77.

Wassmer, P., Schneider, J.L., Pollet, N., Schmitter-Voirin, C., 2004.

Effects of the internal structure of a rock-avalanche dam on the

drainage mechanism of its impoundment, Flims sturzstrom and Ilanz

paleo-lake, Swiss Alps. Geomorphology 61, 3–17.

Wasson, R.J., 2003. A sediment budget for the Ganga–Brahmaputra

catchment. Current Science 84, 1041–1047.

Weidinger, J.T., 2006. Predesign, failure and displacement mechanisms of

large rockslides in the Annapurna Himalayas, Nepal. Engineering

Geology 83, 201–216.

Weidinger, J.T., Wang, J.D., Ma, N.X., 2002. The earthquake-triggered

rock avalanche of Cui Hua, Qin Ling Mountains, P.R. of China—the

benefits of a lake-damming prehistoric natural disaster. Quaternary

International 93-4, 207–214.

Xu, D., 1981. Characteristics of debris flow caused by outburst of glacial

lake in Boqu River, Xizang, China. GeoJournal 17, 569–580.

Yamada, T., 1998. Glacier lake and its outburst flood in the Nepal

Himalaya. Technical Report, Data Center for Glacier Research.