Mud flows and avalanches.pptx

7/27/2019 Mud flows and avalanches.pptx

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MUDFLOWSANDAVALANCHESEr . chhavi gupta


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INTRODUCTIONOFMUDFLOWS

Mud flows are the flows of a mixture of mud , rocks

, vegetation even trees , etc. down the slope of

mountains after a spell of very heavy rains.

Mud flows is similar to landslide the only difference

between landslide and mud flows is in the landslide

mostly saturated soil is involved but in mud flows

the whole mass of water , trees , rock etc. travel like

a river flow at a great speed carrying a mixture as

described above on its path. Many havocs have been caused by these mud

flows in various parts of the earths.


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CONTINUE.

Mud flows are becoming more and more frequent

due to larger amount of rain that are falling now a

days on the earth and also due to the present

spreading of human habitation to the hills and

forests.

In India mud flows usually occur in high mountain

regions as in Kashmir and Himalayan regions.


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ORIGINOFMUDFLOWS

During heavy rains in the mountains , water and

talus deposits on the slope including the large

pieces of rock fragments travel down the slopes.

They may form temporary dams behind which

water gathered.

After sometimes the temporary dam suddenly

breaches and the whole water , rocks , trees ,

vegetation etc. rush down the valley like a river

pushing away everything on its path.

The quantity of mud that these flows carry is so

large that they are called mud flows.


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Mud flows can transport very large pieces of

boulders down the slope.

The density of mudflows is 1.5 t/m3.

Structure like bridges, building , trees etc. which arein the path of mudflows will collapse

The difference between stream and mud flows

contain a lot of talus materials like stones, trees

earth etc. so that it is look very muddy, where as

stream flows consist of water and soil particle only.

Continue.


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GEOLOGICALCONDITIONSFORMUDFLOWS

The debris that are produced by weathering are

dislodged (shifted ) from rocks above steep slopes

accumulate at the base of the slope. That is known

as talus or screen.

Two main or necessary component for mud flows

1) steep mountain slopes with a lot of talus deposit.

2) Very heavy rain.

India- mud flow is reported to be occurring in slopesof Kashmir and other hilly places like Himalayas.

These are the regions of Himalayas where people

go for religious reason.


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PROTECTIONMEASURES

The process of controlling mud flows is difficult as it

takes place in the high hill slopes.

Stabilization of talus and debris is one method of

mud flow control.

If debris is not in large quantity it can be stopped by

means of proper retaining walls and wired fences.

Plating trees having roots deep in the soil along

slopes.

Felling trees (deforestation)and grazing of animals

should be prohibited .


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CONTINUE.

All the roads in these regions likely to have mud

flows, must run at a higher level.

The important at the bottom of valleys that may be

subjected to mud flow from geological

consideration, should be made as over bridges so

that if mud flows happen, traffic is not disrupted.


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WHATISANAVALANCHE?

Technically, an avalanche is any amount of snowsliding down a mountainside. It can be comparedto a landslide, only with snow instead of earth.

Another common term for avalanche is

snowslide. As an avalanche becomes nearer tothe bottom of the slope, it gains speed and power,this can cause even the smallest of snowslides tobe a major disaster.

The word avalanche is derived from the Frenchword avalance meaning descent. An avalanche is amass of snow, often mixed with ice and debriswhich travels down mountain sides, destroying all inits path.


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TYPESOFAVALANCHES

There are two common types of avalanches,.

1) Surface Avalanche

2) Full-Depth Avalanche

1) Surface Avalanche

A Surface Avalanche that occurs when a layer of

snow with different properties slides over another

layer of snow. For example, when a layer of dryloosely packed snow slides over a dense layer of

wet snow


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2) Full-Depth Avalanche

its name would lead you to believe, occurs whenan entire snow cover, from the earth to the surface,slides over the ground.

The nature of the failure of the snowpack isused to morphologically classify the avalanche.

To this point, there are two main types of avalanches:

loose snow avalanches

slab avalancheseither type of avalanche can involve dry or wet

snow.


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For this reason, professionals refer to avalanches as

1) dry loose snow avalanches

2) wet loose snow avalanches

3) dry slab avalanches

4) wet slab avalanches

Loose snow avalanches

most common in steeper terrain, often occur in freshly fallen,low-density surface snow, or in older surface snow that hasbeen softened by strong solar radiation.

In loose snow avalanches, the release usually starts at a

point and the avalanche gradually widens as it travels downthe slope and entrains more snow.

The characteristic shape ofa loose snow avalanche isusually described as resembling a teardrop.

Large, loose snow avalanches may cause slab avalanches.
http://en.wikipedia.org/w/index.php?title=Slab_avalanche&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Slab_avalanche&action=edit&redlink=1


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A POWDERSNOWAVALANCHEIN

THE HIMALAYASNEAR MOUNT EVEREST.


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slab avalanches

Slab avalanches form frequently in new snow, wind

deposited snow, and, less frequently, in old snow,

and have the characteristic appearance ofa block

of snow cut out from its surroundings by

fractures. Elements of slab avalanches include the

following:

a crown fracture at the top of the start zone, flank

fractures on the sides of the start zones, and afracture at the bottom called the stauchwall.


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Slab avalanches, which account for around 90% of

avalanche-related fatalities, form when theapplication of dynamic forces causes catastrophicstructural failure inside a weakness below a slab ofsnow.

Energy for fracture propagation is provided bygravity as the slab falls onto the weak layer .

Fracture propagation can be widespread,sometimes traveling for hundreds of meters, and insome cases kilometers, and can involve snow

depths ranging from 10 centimeters to five or sixmetres.

Avalanches that form when the failure occursbetween the base of the snowpack and the groundare known as full depth slab avalanches.


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Among the largest and most powerful ofavalanches, dry slab avalanches can exceedspeeds of 300 km/h, and masses of 10,000,000tonnes; their flows can travel long distances along

flat valley bottoms and even uphill for shortdistances.

A powder snow avalanche is a turbulent cloud ofsnow and airthat forms when an avalanche travelsover an abrupt change in slope angle, such as a

cliff band. Powder snow avalanches may also form when the

powder cloud of a dry slab avalanche continuesmoving after the core of the avalanche hasstopped.


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There are two main types of slab avalanches,

1) soft slab avalanches2) hard slab avalanche

Both types of avalanches are denoted by debrismorphology:

the debris from a soft slab avalanche is highlygranular, resembling a slurry ofsnowballs and icegrain paste

the debris from a hard slab avalanche is angular,often featuring pieces of the original slab that didnot break up during descent.

Avalanches that descend significant vertical orhorizontal distances may create debris that is notsuitable for classification purposes.


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WHAT CAUSES AVALANCHES?

three primary elements of avalanches: terrain,

weather, and snowpack.

Terrain describes the places where avalanches

occur

weather describes the meteorological conditions

that create the snowpack

snowpack describes the structural characteristics of

snow that make avalanche formation possible.


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TERRAIN

In steep avalanche-prone terrain, traveling

on ridges is generally safer than traversing the

slopes.

Avalanche formation requires a slope where snow

can accumulate, yet has enough steepness for the

snow to accelerate once set in motion by the

combination of mechanical failure (of the

snowpack) and gravity. The angle of the slope that

can hold snow, called the angle of repose, dependson a variety of factors such as crystal form and

moisture content.
http://en.wikipedia.org/wiki/Ridgehttp://en.wikipedia.org/wiki/Angle_of_reposehttp://en.wikipedia.org/wiki/Angle_of_reposehttp://en.wikipedia.org/wiki/Ridge


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On most hills, avalanche hazard can be avoided bysensible choice of route.

Slope angle. Most large slab avalanches run onslopes between 25 and 45 degrees. This range

includes the average angle of coire backwallsand approach slopes to crags.

Ground surface. Smooth ground such as rockslab is pre-disposed to full-depth avalanches.Rough ground such as large boulders will tend

to anchor base layers in position, makingavalanches less likely. Once these boulders arecovered, however, surface avalanche activity isunhindered.


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Slope profile. Convex slopes are generally morehazardous than uniform or concave slopes. Thepoint of maximum convexity is a frequent site oftension fractures, with the release of slabavalanches. (Fig. 3)

Ridges or Buttresses are better choices than openslopes and gullies when avalanche conditionsprevail. The crests of main mountain ridges areusually protected from avalanche, while in climbingsituations, rock belays on ribs and buttresses canoften provide security.

Lee Slopes should be avoided after storms or heavydrifting. Their location will obviously vary accordingto wind direction, but will include the sheltered sideof ridges and plateau rims.


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WEATHER

Avalanches can only occur in a standing snowpack.Typically winter seasons at high latitudes, high altitudes,or both, have weather that is sufficiently unsettled andcold enough for precipitated snow to accumulate into aseasonal snowpack.

Continentality, reflected by the distance from themoderating effects of oceans, is another importantfactor.

Among the critical factors controlling snowpackevolution are: heating by the sun, radiational cooling,vertical temperature gradients in standing snow,

snowfall amounts, and snow types. Generally, mildwinter weather will promote the settlement andstabilization of the snowpack; and conversely very cold,windy, or hot weather will weaken the snowpack.
http://en.wikipedia.org/wiki/Radiational_coolinghttp://en.wikipedia.org/wiki/Temperature_gradienthttp://en.wikipedia.org/wiki/Temperature_gradienthttp://en.wikipedia.org/wiki/Radiational_coolinghttp://en.wikipedia.org/wiki/Radiational_coolinghttp://en.wikipedia.org/wiki/Radiational_cooling


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When a temperature gradient greater than 10 C changeper vertical meter of snow is sustained for more than aday, angular crystals called depth hoaror facets beginforming in the snowpack because of rapid moisturetransport along the temperature gradient.

These angular crystals, which bond poorly to oneanother and the surrounding snow, often become apersistent weakness in the snowpack.

When a slab lying on top of a persistent weakness isloaded by a force greater than the strength of the slaband persistent weak layer, the persistent weak layer canfail and generate an avalanche.
http://en.wikipedia.org/wiki/Depth_hoarhttp://en.wikipedia.org/wiki/Depth_hoar


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Any wind stronger than a light breeze can contribute to a rapidaccumulation of snow on sheltered slopes downwind. Wind slabforms quickly and, if present, weaker snow below the slab maynot have time to adjust to the new load. Even on a clear day,wind can quickly load a slope with snow by blowing snow fromone place to another.

Top-loading occurs when wind deposits snow from the top of aslope; cross-loading occurs when wind deposits snow parallel tothe slope. When a wind blows over the top of a mountain, theleeward, or downwind, side of the mountain experiences top-loading, from the top to the bottom of that lee slope. When thewind blows across a ridge that leads up the mountain, theleeward side of the ridge is subject to cross-loading. Cross-

loaded wind-slabs are usually difficult to identify visually. Snowstorms and rainstorms are important contributors to

avalanche danger. Heavy snowfall will cause instability in theexisting snowpack, both because of the additional weight andbecause the new snow has insufficient time to bond to underlyingsnow layers. Rain has a similar effect.


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In the short-term, rain causes instability because, likea heavy snowfall, it imposes an additional load on thesnowpack; and, once rainwater seeps down throughthe snow, it acts as a lubricant, reducing the naturalfriction between snow layers that holds the snowpacktogether. Most avalanches happen during or soon aftera storm.

Daytime exposure to sunlight will rapidly destabilizethe upper layers of the snowpack if the sunlight isstrong enough to melt the snow, thereby reducing itshardness. During clear nights, the snowpack can re-

freeze when ambient air temperatures fall belowfreezing, through the process of long-wave radiativecooling, or both. Radiative heat loss occurs when thenight air is significantly cooler than the snowpack, andthe heat stored in the snow is re-radiated into theatmosphere.


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This is the most important factor in determining whetheravalanches are likely, and the evolution of the snowpack is entirelydependent on this. However, as the mountaineer can study both ofthese, it is useful to do so.

Many weather variables affect avalanche release and informationcan often be gained before setting out. Readouts from summitweather stations can be beneficial.

The inform ation p rovided on temperature, wind speed anddirect ion of ten enables u seful predict ions to b e made beforeleaving home.

For instance, if a SW wind of 25mph is indicated with freezingtemperatures and snow known to be lying, then it may be assumedthat some avalanche hazard will be building on NE - facing slopes.

Local advice can often be obtained regarding recent weather, whileforecasts are always available. Remember that mountain weather isparticularly difficult to predict and the likely influence ofunexpected changes in weather, both on your own expectation asto snow stability should be considered.


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SNOWPACK

The snowpack is composed of ground-parallellayers that accumulate over the winter.

Each layer contains ice grains that arerepresentative of the distinct meteorologicalconditions during which the snow formed and wasdeposited.

Once deposited, a snow layer continues to evolveunder the influence of the meteorological conditionsthat prevail after deposition.

For an avalanche to occur, it is necessary that asnowpack have a weak layer (or instability) below aslab of cohesive snow.


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In practice the formal mechanical and structural factorsrelated to snowpack instability are not directly observableoutside of laboratories, thus the more easily observedproperties of the snow layers (e.g. penetration resistance,grain size, grain type, temperature) are used as indexmeasurements of the mechanical properties of the snow

(e.g. tensile strength, friction coefficients, shear strength,and ductile strength).

This results in two principal sources of uncertainty indetermining snowpack stability based on snow structure:

First, both the factors influencing snow stability and thespecific characteristics of the snowpack vary widely

within small areas and time scales, resulting in significantdifficulty extrapolating point observations of snow layersacross different scales of space and time.


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Second, the relationship between readily observable snowpackcharacteristics and the snowpack's critical mechanical propertieshas not been completely developed.

o While the deterministic relationship between snowpackcharacteristics and snowpack stability is still a matter ofongoing scientific study, there is a growing empiricalunderstanding of the snow composition and deposition

characteristics that influence the likelihood of an avalanche.o Observation and experience has shown that newly fallen snow

requires time to bond with the snow layers beneath it, especiallyif the new snow falls during very cold and dry conditions.

o If ambient air temperatures are cold enough, shallow snowabove or around boulders, plants, and other discontinuities in

the slope, weakens from rapid crystal growth that occurs in thepresence of a critical temperature gradient.


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Large, angular snow crystals are an indicator weaksnow, because such crystals have fewer bonds per unitvolume than small, rounded crystals that pack tightlytogether.

Consolidated snow is less likely to slough than loosepowdery layers or wet isothermal snow; however,consolidated snow is a necessary condition for theoccurrence ofslab avalanches, and persistentinstabilities within the snowpack can hide below well-consolidated surface layers.

Uncertainty associated with the empirical understandingof the factors influencing snow stability leads mostprofessional avalanche workers to recommendconservative use of avalanche terrain relative to currentsnowpack instability.
http://en.wikipedia.org/w/index.php?title=Slab_avalanche&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Slab_avalanche&action=edit&redlink=1


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During examining the snow back the following

features should be looked for:

Adjacent layers of different hardness.

Water drops squeezed out of a snowball made

from any layer.

Layers of ice.

Layers of graupel (rounded, heavily rimmed

pellets). These act like a layer of ball bearings

in the snowpack.


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Feathery or faceted crystals.

Layers of loose, uncohesive grains.

Air space.

Very soft layers. (fist penetrates easily)Any of the above might be the source

of a dangerous weakness in the snowpack.


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These observations may be supplemented by ashovel test . For this, a shovel is notnecessary. Your ice axe and gloved hands willsufficent.

Having made the snowpit observations, isolate a

wedge shaped block, cutting down to the top of thenext identified layer. If the top layer then slidesspontaneously, clearly a very poor bond existsbetween the layers. If it does not, then try to ratethe ease with which you can pull the block off byinserting your shovel/axes/hands behind the block

and pulling. Do this for each suspect layer in your pit.

Performing this test many times will help you tobuild up a "feeling" for the stability of the layers.


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Techniques such as this should enable you tomake an educated hazard assessment.Remember that your snowpit observations willhold good only for slopes of similar orientation

and altitude to your test pit. You will need toextrapolate for situations higher up, for instancebelow cornices, where surface wind slab layersmay be much thicker, etc.

An attempt should be made to rate the slope

Safe, Marginal, or Unsafe. Even if a slope isMarginal or Unsafe, it may be possible tochoose a safe route by careful selection.


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CORNICES

Many avalanches are cornice-triggered. In

general, climbing below cornices should be

avoided:

During snow storms or heavy drifting

Immediately (24-48 hours) after these.

During heavy thaw or sudden temperature rise.

When walking above cornices, take care to give

them a wide berth. Fig. 2 below, shows the

possible fracture line.


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PREVENTION

preventative measures are employed in areas whereavalanches pose a significant threat to people, such as skiresorts and mountain towns, roads and railways.

There are several ways to prevent avalanches and lessentheir power and destruction; active preventative measures

reduce the likelihood and size of avalanches by disrupting thestructure of the snowpack; passive measures reinforce andstabilize the snowpack in situ.

The simplest active measure is by repeatedly traveling on asnowpack as snow accumulates; this can be by means ofboot-packing, ski-cutting, or machine

grooming. Explosives are used extensively to preventavalanches, by triggering smaller avalanches that break downinstabilities in the snowpack, and removing over burden thatcan result in larger avalanches.
http://en.wikipedia.org/wiki/Ski_resorthttp://en.wikipedia.org/wiki/Ski_resorthttp://en.wikipedia.org/wiki/Explosivehttp://en.wikipedia.org/wiki/Explosivehttp://en.wikipedia.org/wiki/Ski_resorthttp://en.wikipedia.org/wiki/Ski_resort


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Explosive charges are delivered by a number of methodsincluding hand tossed charges, helicopter dropped bombs,Gazex concussion lines, and ballistic projectiles launched byair cannons and artillery.

Passive preventive systems such as Snow fences and lightwalls can be used to direct the placement of snow. Snow

builds up around the fence, especially the side that faces theprevailing winds.

Downwind of the fence, snow buildup is lessened. This iscaused by the loss of snow at the fence that would have beendeposited and the pickup of the snow that is already there bythe wind, which was depleted of snow at the fence. When

there is a sufficient density oftrees, they can greatly reducethe strength of avalanches. They hold snow in place and whenthere is an avalanche, the impact of the snow against thetrees slows it down. Trees can either be planted or they canbe conserved, such as in the building of a ski resort, to reducethe strength of avalanches.
http://en.wikipedia.org/wiki/Snow_fencehttp://en.wikipedia.org/wiki/Windhttp://en.wikipedia.org/wiki/Treehttp://en.wikipedia.org/wiki/Treehttp://en.wikipedia.org/wiki/Windhttp://en.wikipedia.org/wiki/Snow_fence


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To mitigate the effect of avalanches, artificial barrierscan be very effective in reducing avalanche damage.There are several types. One kind of barrier (snow net)uses a net strung between poles that are anchoredby guy wires in addition to their foundations. Thesebarriers are similar to those used forrockslides. Anothertype of barrier is a rigid fence-like structure (snow fence)and may be constructed ofsteel, wood or pre-stressedconcrete.

They usually have gaps between the beams and arebuilt perpendicular to the slope, with reinforcing beams

on the downhill side. Rigid barriers are often consideredunsightly, especially when many rows must be built.

They are also expensive and vulnerable to damage fromfalling rocks in the warmer months.
http://en.wikipedia.org/wiki/Snow_nethttp://en.wikipedia.org/wiki/Guy_wirehttp://en.wikipedia.org/wiki/Rockslidehttp://en.wikipedia.org/wiki/Snow_fencehttp://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Woodhttp://en.wikipedia.org/wiki/Concretehttp://en.wikipedia.org/wiki/Concretehttp://en.wikipedia.org/wiki/Woodhttp://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Snow_fencehttp://en.wikipedia.org/wiki/Rockslidehttp://en.wikipedia.org/wiki/Guy_wirehttp://en.wikipedia.org/wiki/Snow_net


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In addition to industrially manufactured barriers,landscaped barriers, called avalanche dams stop ordeflect avalanches with their weight and strength. Thesebarriers are made out of concrete, rocks or earth. They

are usually placed right above the structure, road orrailway that they are trying to protect, although they canalso be used to channel avalanches into other barriers.

Occasionally, earth mounds are placed in theavalanche's path to slow it down.

Finally, along transportation corridors, large shelters,called snow sheds, can be built directly in the slide pathof an avalanche to protect traffic from avalanches.
http://en.wikipedia.org/wiki/Avalanche_damhttp://en.wikipedia.org/wiki/Earth_moundhttp://en.wikipedia.org/wiki/Snow_shedhttp://en.wikipedia.org/wiki/Snow_shedhttp://en.wikipedia.org/wiki/Earth_moundhttp://en.wikipedia.org/wiki/Avalanche_dam


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SAFETY

Terrain management - it involves reducing the exposure of an

individual to the risks of traveling in avalanche terrain by carefullyselecting what areas of slopes to travel on. Features to becognizant of include not under cutting slopes (removing thephysical support of the snowpack), not traveling over convex rolls(areas where the snowpack is under tension), staying away fromweaknesses like exposed rock, and avoiding areas of slopes thatexpose one to terrain traps (gulleys that can be filled in, cliffs

over which one can be swept, or heavy timber into which one canbe carried).

Group management - Group management is the practice ofreducing the risk of having a member of a group, or a wholegroup involved in an avalanche.

Minimize the number of people on the slope, and maintainseparation. Ideally one person should pass over the slope into anarea protected from the avalanche hazard before the next oneleaves protective cover.

Route selection should also consider what dangers lie above andbelow the route, and the consequences of an unexpectedavalanche (i.e., unlikely to occur, but deadly if it does).


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Stop or camp only in safe locations. Wear warm gear to delay hypothermia if buried.

In determining the size of the group balance the hazard of nothaving enough people to effectively carry out a rescue withthe risk of having too many members of the group to safelymanage the risks.

It is generally recommended not to travel alone, becausethere will be no-one to witness your burial and start therescue.

Additionally, avalanche risk increases with use; that is, themore a slope is disturbed by skiers, the more likely it is that anavalanche will occur.

Most important of all practice good communication within agroup including clearly communicating the decisions aboutsafe locations, escape routes, and slope choices, and havinga clear understanding of every members skills in snow travel,avalanche rescue, and route finding.
http://en.wikipedia.org/wiki/Skiinghttp://en.wikipedia.org/wiki/Skiing


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Risk Factor Awareness - Risk factor awareness in avalanche safetyrequires gathering and accounting for a wide range of information suchas the meteorological history of the area, the current weather and snowconditions, and equally important the social and physical indicators of thegroup.

Leadership - Leadership in avalanche terrain requires well defineddecision-making protocols that use the observed risk factors. These

decision-making frameworks are taught in a variety of courses providedby national avalanche resource centers in Europe and North America.Fundamental to leadership in avalanche terrain is honestly assessingand estimating the information that was ignored or overlooked. Recentresearch has shown that there are strong psychological and groupdynamic determinants that lead to avalanche involvement.

Control measures: In many areas, regular avalanche tracks can beidentified and precautions can be taken to minimise damage, such as theprevention of development in these areas, the construction of avalanchesheds over existing roads and railways and the use of tunnels for newroad and rail links. Avalanches cause danger when their path cannot bepredicted and are a major hazard for skiers and mountaineers.


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TRAVEL IN HAZARD AREAS

It is rarely essential to negotiate an avalanche-prone slope. It isusually possible to find another way, or retreat. 90% OF ALLAVALANCHES INVOLVING HUMAN SUBJECTS ARE TRIGGERED BYTHEIR VICTIMS.

If it is essential to proceed, the following should be borne in mind:

Solo travellers in avalanche terrain run particularly grave hazards.

Skiers are in greater danger than walkers - the lateral cutting actionof skis readily releases unstable snow. All off-piste skiers shoulduse avalanche transceivers and have them SWITCHED ON beforeleaving base. They should carry collapsible probes andshovels. Climbers and walkers should also consider the use ofthese items.

Direct descent or ascent is safer than traversing.

Go one at a time - the others should closely observe the progress ofthe person on the suspect slope.

Close up clothing. Wrap scarf or other item around mouth andnose.

Belay if possible. This is rarely feasible on wide, open slopes.


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IF CAUGHT

In most avalanche situations, any defensive action is verydifficult. Movement relative to the debris is oftenimpossible. However, some of the following may be useful.

Try to delay departure by plunging ice axe into the undersurface. This may help to keep you near the top of the slide.

Shout. Others may see you.

Try to run to the side, or jump up slope above the fracture. If hard slab, try to remain on the top of a block.

Get rid of gear, sacks, skis etc.

Try to roll like a log off the debris.

Swimming motions sometimes help.

As the avalanche slows down, you may be able to get somepurchase on the debris. Make a desperate effort to get to thesurface, or at least get a hand through.


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IF BURIED

Keep one hand in front of your face and try to

clear/maintain an air space.

Try to maintain space for chest expansion by

taking and holding a deep breath.

Try to avoid panic and conserve energy. Your

companions are probably searching for you.


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AVALANCHE RESCUE

If you witness an avalanche burial: Observe the victim's progress and if possible mark the

point of entry and point at which last seen.

Check for further avalanche danger.

Make a QUICK SEARCH of the debris surface.

- LOOK for any signs of the victim.- LISTEN for any sounds.- PROBE the most likely burial spots.

Make a SYSTEMATIC SEARCH, probing the debris withaxes or poles.

Send for help.

KEEP SEARCHING until help arrives. remember, you are the buried victim's only real chance of

live rescue.

Although survival chances decline rapidly with durationof burial, they do not reach zero for a long time.

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Mud flows and avalanches.pptx