Hail & Wind Threats!

Texas Mitigation Leadership Forum Austin, TX June 28, 2010

Steven Cooper Deputy Regional Director Southern Region Severe Impacts

• Tornadoes

• Hail

• Winds

• Flooding Rainfall Overview Texas Impacts

Thunderstorms • Hail – Examples – Causes – Frequency – Factoids (Record Size/Events/Costs) • Wind – Examples – Causes – Frequency – Factoids (Record Size/Events/Costs) May 16, 2010 Hailstorm Severe Hail Damage Examples Severe Hailstone Shapes & Sizes Hail Size Range Example

Softball = 4”

Quarter = 1” Hail Formation Process Thunderstorm updrafts carry water As hailstones fall, they merge with droplets high into the storm where raindrops. Updrafts then carry them they freeze. back up into sub freezing storm regions. How strong of an updraft to support hail?

Hailstone Size Size (in.) Updraft Speed (mph) PEA ¼ 24 PENNY ¾ 40 QUARTER 1 49 HALF DOLLAR 1 ¼ 54 GOLF BALL 1 ¾ 64 TENNIS BALL 2 ½ 77 BASEBALL 2 ¾ 81 SOFTBALL 4 98 GRAPEFRUIT 4 ½ 103 HAIL (2” or more in diameter) Days HAIL Factoids

• LARGEST – 7 Inch diameter (circum of 18 ¾”) in Aurora, Nebraska on June 22, 2003.

• HEAVIEST – 1.67 pounds in Coffeyville, Kansas on September 3, 1970.

• UPDRAFT SPEED – Around 100 mph (softball).

• FALL SPEED – Up to 120 mph.

• ANNUAL U.S. DAMAGE – Approximately $1 Billion per year to crops/property.

• COSTLIEST - $2 Billion, Fort worth, Texas, May 5, 1995 / I 70 Corridor in Eastern Kansas, Missouri, and SW , April 10, 2001. Texas Hailstone Factoids

Largest Diameter Reported • 8.00“ - Winkler County - May 31, 1960 • 7.50” - Young County - April 14, 1965 • 7.05” - Burleson County - Dec. 17, 1995 • 6.00” - Ward County - May 10, 1991

Source: NOAA - National Climatic Data Center Texas Hailstone Factoids

Damage Estimated from Hail (1950-2010)

• Property Damage – Over 3 Billion! (Conservative)

• Crop Damage – Over 400 Million! (Under reported)

Source: NOAA - National Climatic Data Center – Everyday Threat Schematic of Downburst Downburst Damage

Source: NWS – St Louis, MO

Source: Dr. Ted Fujita

Source: NWS – Lacrosse, WI Downburst Impact on Aircraft Downbursts – How they Form Thunderstorm Days per Year Downburst Winds - 58 MPH or More

“Pulse” type Typical over SE in summer Downburst Winds - 75 MPH or More U.S. Downburst Factoids

• Speeds can reach over 100 mph (see record!). • Most downbursts speeds between 60 – 80 mph. • Damage can resemble that from a . • Every thunderstorm produces a downburst! – Most are weak. Strength of downburst is what matters. – At 40 – 57 MPH, downbursts typically cause minor damage. – Downbursts equal to/greater than 58 mph are considered severe and may cause tornado like damage. Strongest Downburst Recorded

• 130 MPH Peak Gust • 2:11 PM (7 minutes after Air Force One landed with the President on board)! • August 01, 1983 • Andrews Air Force Base • Washington D.C. Texas Downburst Factoids

Damage Estimated from Downbursts (1950-2010) • Property Damage – Over 800 Million! (Conservative)

• Crop Damage – Over 85 Million! (Under reported)

Fatal Downburst • Dallas – Fort Worth Airport (DFW) • August 2, 1985 • 80 MPH • Downed Delta Flight 191 (Lockheed L-1011) • 135 Fatalities [email protected]

www.srh.weather.gov

JetStream