Tornadoes and Thunderstorms

Tornadoes and Thunderstorms

Facts & Statistics: Tornadoes

TORNADOES

A tornado is a violently rotating column of air that extends from a thunderstorm and comes into contact with the ground, according to the National Oceanic and Atmospheric Administration (NOAA). In an average year about 1,000 tornadoes are reported nationwide, according to NOAA. Tornado intensity is measured by the enhanced Fujita (EF) scale. The scale rates tornadoes on a scale of 0 through 5, based on the amount and type of wind damage. It incorporates 28 different “damage indicators,” based on damage to a wide variety of structures ranging from trees to shopping malls.

 

THE FUJITA SCALE FOR TORNADOES

    Original F scale (1) Enhanced F scale (2)
Category Damage Wind speed (mph) 3-second
gust (mph)
F-0 Light 40-72  65-85
F-1 Moderate 73-112 86-110
F-2 Considerable 113-157  111-135
F-3 Severe 158-207 136-165
F-4 Devastating 208-260 166-200
F-5 Incredible 261-318 Over 200
(1) Original scale: wind speeds represent fastest estimated speeds over ¼  mile.
(2) Enhanced scale: wind speeds represent maximum 3-second gusts. Implemented on February 1, 2007.

Source:  U.S. Department of Commerce, National Oceanic and Atmospheric Administration.

 

THE 2013 TORNADO SEASON

A large outbreak of over 60 tornadoes hit the Midwest and southern Great Plains from May 18 to 20, including an EF5 tornado (the most powerful category) that hit Moore, Oklahoma. Thousands of homes and other buildings were destroyed. According to Munich Re, overall insured losses from the outbreak were estimated to total $1.8 billion. From May 28 to 31 another large outbreak occurred over the southern Plains. The area near El Reno, Oklahoma, was hit by an EF3 tornado that had the largest diameter ever observed in a tornado, 2.6 miles. Overall insured losses from the outbreak were estimated at $1.4 billion by Munich Re. From November 16 to 17 a strong storm system hit the Midwest, causing at least six deaths, according to the National Weather Service (NWS). The NWS estimates that 65 tornadoes touched down, mostly in Illinois but also in Indiana and Kentucky. Munich Re says this was the largest tornado outbreak ever observed in the month of November and estimated that insured losses from this event were $900 million. For updated information see NOAA Watch. In 2012, November was one of the least active months for tornadoes. (See chart below.)

The devastating tornadoes that hit Oklahoma in May bring to mind a powerful string of tornadoes that hit Oklahoma, Kansas, Texas, Georgia and 13 other states in 1999. Those tornadoes resulted in $1.5 billion in insured losses ($2.0 billion in 2012 dollars) in all the affected states, according to Property Claim Services (PCS), a division of Verisk Analytics. The damage to Oklahoma was nearly $1.0 billion ($1.4 billion in 2012 dollars), according to PCS. The costliest U.S. catastrophe involving tornadoes, based on insured losses, occurred in April 2011. It hit Tuscaloosa, Alabama, and other areas and cost $7.4 billion in insured damages in 2012 dollars. That event was the 10th costliest U.S. catastrophe, based on insured losses, according to PCS. The second costliest catastrophe involving tornadoes, based on insured losses, struck Joplin, Missouri, and other locations in May 2011. The catastrophe cost $7.0 billion in insured losses in 2012 dollars. (See chart below). The National Weather Service posts updated information on tornadoes.

PCS reported that in 2013 there were 29 catastrophes involving thunderstorms, which frequently include tornadoes. These catastrophes resulted from 24 thunderstorms and caused $12.87 billion in insured losses. The U.S. experiences more tornadoes than any other country in the world, according to a 2013 report by Lloyd’s of London. (See Executive Summary, page 4 of Tornadoes a Rising Risk? for additional findings and statistics.)

Munich Re includes tornadoes in the "Severe Thunderstorms" category shown below.

THE 2014 TORNADO SEASON

Preliminary NOAA data show that there were 745 tornadoes in 2014 through August 2, compared with 729 during the same period the previous year. On April 27, 30 tornadoes formed in at least seven states (Arkansas, Iowa, Nebraska, Kansas, Oklahoma, Mississippi and Louisiana). Nineteen fatalities were reported with 16 in Arkansas, two in Oklahoma and one in North Carolina. Many homes and buildings were damaged or destroyed in Arkansas, Oklahoma and Kansas, according to the Federal Emergency Management Agency (FEMA).

 

NATURAL DISASTER LOSSES IN THE UNITED STATES, 2013

Source: © 2014 Munich Re, NatCatSERVICE. As of January 2014.

View Archived Graphs

 

 

NUMBER OF TORNADOES AND RELATED DEATHS PER MONTH, 2013 (1)

(1) Excludes Puerto Rico. Counts tornadoes crossing state lines as one event.

Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service.

View Archived Graphs

 

 

THE TEN MOST COSTLY U.S. CATASTROPHES INVOLVING TORNADOES (1)

($ millions)

      Estimated insured loss (2)
Rank Date Location Dollars when
occurred
In 2013
dollars (3)
1 Apr. 22-28, 2011 AL, AR, GA, IL, KY, LA, MO,
MS, OH, OK, TN, TX, VA
$7,300 $7,540
2 May 20-27, 2011 AR, GA, IA, IL, IN, KS, KY,
MI, MN, MO, NC, NE, NY,OH,
OK, PA, TN, TX, VA, WI
6,900 7,127
3 May 2-11, 2003 AL, AR, CO, GA, IA, IL, IN,
KS, KY, MO, MS, NC, NE,
OH, OK, SC, SD, TN
3,205 3,938
4 Oct. 4-6, 2010 AZ 2,700 2,843
5 Apr. 6-12, 2001 AR, CO, IA, IL, IN, KS, KY, MI, MN, MO,
NE, OH, OK, PA, TX, WI
2,200 2,799
6 Mar. 2-3, 2012 AL, GA, IN, KY, OH, TN 2,500 2,538
7 Apr. 28-29, 2012 IL, IN, KY, MO, TX 2,500 2,538
8 May 12-16, 2010 IL, MD, OK, PA, TX 2,000 2,106
9 Apr. 27-May 3, 2002 AR, GA, IL, IN, KS, KY, MD, MO, MS
NC, NY, OH, PA, TN, TX, VA, WV
1,675 2,099
10 Apr. 13-15, 2006 IA, IL, IN, WI 1,850 2,080

(1) Based on data available as of July 8, 2014.                
(2) Property coverage only. In addition to losses due to tornadoes themselves, amounts may include losses due to hail, wind and flooding during the same events.                
(3) Adjusted for inflation through 2013 by ISO using the GDP implicit price deflator.                
                
Source: The Property Claim Services® (PCS®) unit of ISO®, a Verisk Analytics® company.

 

 

TOP TEN STATES, BY NUMBER OF TORNADOES, 2013 (1)

Rank State Number of tornadoes
1 Illinois 69
2 Nebraska 65
3 Texas 65
4 Kansas 58
5 Oklahoma 56
6 Missouri 54
7 Kentucky 50
8 Tennessee 43
9 Indiana 41
10 Florida 37

(1) Tornadoes that cross state lines are counted as a single event in each state.

Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service.

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TORNADOES AND RELATED DEATHS BY STATE, 2013 (1)

State Tornadoes Fatalities Rank (2) State Tornadoes Fatalities Rank (2)
Alabama 27 0 15 Montana 10 0 25
Alaska 0 0 (3) Nebraska 65 0 2
Arizona 1 0 38 Nevada 0 0 (3)
Arkansas 30 2 13 New Hampshire 0 0 (3)
California 6 0 31 New Jersey 3 0 33
Colorado 27 0 15 New Mexico 0 0 (3)
Connecticut 3 0 33 New York 9 0 27
Delaware 1 0 38 North Carolina 12 0 23
D.C. 0 0 (3) North Dakota 17 0 19
Florida 37 0 10 Ohio 26 0 15
Georgia 27 1 15 Oklahoma 56 34 5
Hawaii 0 0 (3) Oregon 3 0 33
Idaho 5 0 32 Pennsylvania 9 0 27
Illinois 69 8 1 Rhode Island 0 0 (3)
Indiana 41 0 9 South Carolina 8 0 29
Iowa 30 1 13 South Dakota 15 0 20
Kansas 58 0 4 Tennessee 43 0 8
Kentucky 50 0 7 Texas 65 7 2
Louisiana 34 0 12 Utah 1 0 38
Maine 1 0 38 Vermont 0 0 (3)
Maryland 10 0 25 Virginia 3 0 33
Massachusetts 1 0 38 Washington 2 0 37
Michigan 13 0 22 West Virginia 0 0 (3)
Minnesota 11 0 24 Wisconsin 15 0 20
Mississippi 36 2 11 Wyoming 8 0 29
Missouri 54 0 6 United States 942 (4) 55  

(1) Ranked by total number of tornadoes.
(2) States with the same number receive the same ranking.
(3) State had no tornadoes in 2013.
(4) The U.S. total will not match data used in other charts because this chart counts a tornado that crosses state lines as more than one event.

Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service.

View Archived Tables

 

 

TORNADOES AND RELATED DEATHS IN THE UNITED STATES, 1994-2013 (1)

Year Tornadoes Deaths Year Tornadoes Deaths Year Tornadoes Deaths
1994 1,082 69 2001 1,216 40 2008 1,692 126
1995 1,234 30 2002 941 55 2009 1,156 21
1996 1,173 25 2003 1,376 54 2010 1,282 45
1997 1,148 67 2004 1,819 36 2011 1,691 553
1998 1,424 130 2005 1,264 38 2012 939 70
1999 1,345 94 2006 1,103 67 2013 908 55
2000 1,071 40 2007 1,098 81      

(1) Excludes Puerto Rico. Counts tornadoes crossing state lines as one event.

Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service.

View Archived Tables

 

 

U.S. THUNDERSTORM EVENTS, 1993-2012 (1)

Year Insured loss
(2012 $billions)
1993 $3.5
1994 3.9
1995 6.6
1996 4.5
1997 3.0
1998 8.5
1999 6.4
2000 4.3
2001 5.7
2002 5.4
2003 9.6
2004 4.2
2005 3.2
2006 9.0
2007 3.3
2008 11.2
2009 10.3
2010 11.4
2011 26.7
2012 14.9

(1) Includes tornado events.
(2) Adjusted for inflation by Munich Re.

Source: Source: © 2013 Munich Re, NatCatSERVICE. As of May 2013.

 

 

U.S. THUNDERSTORM LOSS TRENDS, 1980-2013

(Annual totals 1980–2013)

Source: 2014 Munich Re, NatCatSERVICE; Property Claim Services (PCS), a  division of Verisk Analytics. As of January 2014.

View Archived Graphs