Jeffrey LindnerMeteorologist

Harris County Flood Control DistrictOctober 11, 2011

2010-2011 Drought

Texas Annual Rainfall

Texas Annual Rainfall 1895-2010

Texas Annual Temperature 1895-2010

Notice Any Trends?

Texas Spring Rainfall 1895-2010

Less Spring rainfall since 1950

Texas Summer Rainfall 1895-2010

Greater summer rainfall since 1960

Texas Fall Rainfall 1895-2010

Greater Fall rainfall since 1960

Texas Winter Rainfall 1895-2010

Less winter rainfall since 1950

Texas Climate Trends

• Drier winter and spring seasons since 1950• Wetter summer and fall seasons since 1960• Overall Texas annual rainfall has been greater since 1960 compared 1895-1960• Drought was much more common, long term, and severe pre 1960• Annual temperatures have been above average since 1996

2010 Texas Rainfall

2010 Texas Rainfall Departures

DRY

WET

2010-2011 Texas Rainfall Departures (Sept 10- Oct 11)

2011 Drought Conditions

2011 Summer Heat

Days at or above 100:Houston IAH: 46 (32 in 1980)Hobby: 18 (13 in 1998/2000)Conroe: 53 (42 in 1998)Huntsville: 72 (43 in 1980)College Station: 69 (58 in 1917)Dallas: 71 (69 in 1980)Waco: 90 (63 in 1980)Austin Mabry: 90 (69 in 1925)San Antonio: 57 (59 in 2009)Del Rio: 85 (78 in 1953)

Most Consecutive 100 degree days:Houston IAH: 24 (14 in 1980)Austin: 27 (21 in 2001)Dallas: 40 (42 in 1980)Waco: 44 (42 in 1980)

• Houston tied all-time record high of 109 on 8-27-11• Galveston: 100 on 8-27-11 for only the 7th time ever• Hottest June-August (summer) period ever!

Top 4 Warmest months for Texas ever:July 2011: 87.2July 1998: 86.5July 1980: 86.3August 1952: 85.7

2011 Drought Conditions Lake Levels and Capacity Oct 21

Lake Conroe: -6.86 (71%)Lake Houston: -5.60 (74%)Lake Livingston: -4.00 (83%)Lake Somerville: -10.03 (39%)Lake Texana: -11.59 (44%)Lake Buchanan: -28.45 (41%) Lake Travis: -52.86 (36%)Lake Georgetown: -25.36 (34%)Toledo Bend: -11.90 (59%)Sam Rayburn: -13.14 (56%)

Lake Houston

Lake Travis

Lake Travis

Conservation Storage Statistics -TWDB

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Conservation Storage Statistics -TWDB

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2011 Drought Conditions

March 30

October 19

Mandatory: 636Voluntary: 311

Mandatory: 33Voluntary: 34

Texas Wildfires 11/15/2010-10/19/2011

• 3.8 million acres burned• 24,279 fires• 51,617 structures threatened• 7,223 structures burned• 49 states responding• 175 million acre ft of timber destroyed worth 1.6 billion

April 2011

4 out of the 10 largest TX fires occurred in April 2011

Texas Wildfires – Labor Day Weekend

Bastrop Complex:34,036 acres2 fatalities1554 homes lost5,000 evacuated1351 ground personnel, 14 aircraft

Tri-County:18,638 acres63 homes lost (23 damaged)8,000 evacuated698 ground personnel, 16 aircraft20.8 million acre feet of timber burned (12.8 million in value)

12 large fires, Labor Day 2011

Over 2,000 homes lost in 3-4 days

Texas Burn Ban Map

229 out of 254 counties under burn bans, old record was 221 in 2006

Fire Fuel ConditionsKBDI Index

AUSTIN 632 GALVESTON 606BRAZOS 664BURLESON 708BASTROP 615COLORADO 682 FORT BEND 648 GRIMES 638 HARRIS 552 HOUSTON 741 JACKSON 690 LIBERTY 677 MADISON 692 MATAGORDA 614 MONTGOMERY 630POLK 704SAN JACINTO 647 TRINITY 714 WALKER 710 WALLER 568 WASHINGTON 671 WHARTON 668

Fall Fire Weather Conditions

• Low RH (20-30%)• Strong Winds (15-25mph)• Critical days behind cold fronts• Conditions will worsen after first freeze• Pine areas most risk• Threat for wind driven crown fires

Steiner Ranch

2010-2011 DroughtTop 5 Driest Feb-Oct 19 Periods for Houston: 2011 – 10.20 in (22.6% of normal)1917 - 13.93 in1930 - 15.89 in1956 – 15.95 in1925 – 16.69 in

Top 5 Driest Jan 1-Oct 14 Periods for Houston: 1917-15.22 in2011-15.25 in1956- 19.24 in1930 – 19.41 in1988 – 19.49 in

1.1950-1957 (Sept 1956 peak)2. 2010-?3. 1916-1918 (Aug 1918 peak)4. 1924-1925 (July 1925 peak)5. 1999-2000 (Sept 2000 peak

Texas Drought Rankings

3.73 inches of rain required at IAH to move to second place and .76 inches at Hobby (5.11 fell at Hobby on Oct 9…still in first place)

Drought Lowest PDSI 2010-2011 -7.97 AUG 20111951-1957 -7.80 SEP 1956 1916-1918 -7.09 AUG 1918 1924-1925 -6.10 JUL 1925 1999-2000 -5.51 SEP 2000

2010-2011 DroughtDriest 12-Month Period Ever (September 22, 2010 to September 23, 2011)

Location Rainfall (in) (9-22-10 to 9-23-11) Previous Rainfall Record (in) Record Exceedance (in)

Bellville 12.75 19.90 (1987-88) 7.15

Brenham 16.10 13.76 (1924-25) 2.34

Columbus 14.84 17.57 (1955-56) 2.73

Conroe 17.42 22.51 (1924-25) 5.09

Freeport 17.98 24.77 (1953-54) 6.79

BUSH IAH 17.71 23.25 (1916-17) 5.54

Huntsville 15.31 18.09 (1916-17) 2.78

Katy 14.67 27.31 (1987-88) 12.64

Livingston 17.77 31.35 (1947-48) 13.58

Somerville 14.83 19.77 (1970-71) 4.94

Tomball 12.44 22.15 (1960-61) 9.71

Wash on the Brazos 14.52 24.44 (1955-56) 9.92

Red: broke previous record by over 10 inchesOrange: broke previous record by over 5 inches

2010-2011 Drought

Bellville: -28.19Brenham: -28.43College Station: -25.05Columbus: -27.88Conroe: -30.64Freeport: -31.80Hobby: -27.44IAH: -28.57Katy: -26.20Livingston: -34.45Matagorda: -28.83Huntsville: -31.76Victoria: -28.51Tomball: -36.10

Rainfall Deficits (Oct 1 2010 to Oct 14 2011)

Galveston: -40.91 Houston IAH: -28.89 Houston Hobby: -32.78 College Station: -29.20 Richmond: -38.51Bay City: -36.74Wharton: -34.46Livingston: -43.28

Rainfall Deficits since Hurricane Ike

Have been in mild drought since Ike, but the last 8 months have been brutal

October 2010 to September 2011: Driest 1-year period ever for state of TX

2010-2011 Drought

2011

Driest water year on record for Texas

2010-2011 Drought

• 2nd worst in SE TX based on rainfall behind 1917-1918 (likely worst in some areas) • 2nd worst drought in TX history (behind 1950’s)• Driest April ever at Houston (.11 of an inch), driest Spring ever for Houston• Driest year to date ever for the City of Houston• At least 5.1 billion in economic losses so far, 90% of corn crop failed•Hay no longer available for cattle•Tremendous impacts on livestock, vegetation, economy

•2.1 million trees lost, estimate 66 million in two years (10% of area canopy)

2010-2011 Drought

Most areas would require 25-35 inches of rainfall to bring them to near normal conditions and end the drought

2011-2013 ENSO Forecast Models

La Nina

El Nino

Neutral

La Nina Impacts

La Nina Impacts

2011 Drought Forecast

Rainfall Forecast

8-14 days

1 month

3 months

Questions