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 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.)
The Fujita Scale For Tornadoes
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- Original scale: wind speeds represent fastest estimated speeds over one quarter of a mile.
- Enhanced scale: wind speeds represent maximum 3-second gusts.
Source: U.S. Department of Commerce, National Oceanic and Atmospheric Administration.
INSURED LOSSES
The United States experiences more tornadoes than any other country. Tornadoes accounted for 40.2 percent of insured catastrophe losses from 1996 to 2015, according to Verisk’s Property Claim Services (PCS). In 2015 insured losses from U.S. tornadoes/thunderstorms totaled $9.6 billion, down from $12.3 billion in 2014. The National Oceanic and Atmospheric Administration notes that tornadoes can happen any time of year. The costliest U.S. catastrophe involving tornadoes, based on insured losses, occurred in April 2011. It hit Tuscaloosa, Alabama, and other areas, and cost $7.8 billion in insured damages (in 2015 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 $7.3 billion in insured losses in 2015 dollars. (See chart below.) The National Weather Service posts updated information on tornadoes.
THE 2016-2017 TORNADO SEASONS
Preliminary NOAA reports show that there were about 138 tornadoes in January 2017 compared with a January average of 16 for the three years from 2014 to 2016. These tornadoes killed 20 people in January 2017 compared with 17 in all of 2016. There were four deaths in Mississippi on January 21. There were 16 deaths in Georgia on January 22. On February 7th a powerful tornado hit Eastern New Orleans causing major damage in areas devastated by Hurricane Katrina. The tornado was one of several twisters spawned as severe thunderstorms moved across the Southeast.
Preliminary NOAA data show that there were about 985 tornadoes in 2016, compared with 1,177 in 2015. On January 17, tornadoes developed in Florida with two fatalities. On February 23 and 24 tornadoes formed in Louisiana, Mississippi and Virginia resulting in two fatalities in Louisiana, one in Mississippi and four in Virginia. February 23 was the most active tornado day in 2016, when 52 storms formed. On April 27, one fatality resulted from a tornado in Texas and on May 9 tornadoes in Oklahoma killed two people.
Natural Catastrophe Losses In The United States, 2016
(Based on perils)
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Source: © 2017 Munich Re, NatCatSERVICE; Property Claim Services (PCS®)*, a Verisk Analytics® business. As of February 2017.
Number Of Tornadoes And Related Deaths Per Month, 2015 (1)
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(1) Excludes Puerto Rico. A tornado that crosses state lines is counted as a single event in this chart.
Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service.
Top 10 Costliest U.S. Catastrophes Involving Tornadoes (1)
($ millions)
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- Based on data through May 31, 2016.
- Property coverage only. In addition to losses due to tornadoes themselves, amounts may include losses due to hail, wind and flooding during the same event.
- Adjusted for inflation through 2015 by ISO using the GDP implicit price deflator.
Source: Property Claim Services (PCS®), a Verisk Analytics® business.
Top 10 States By Number Of Tornadoes, 2015 (1)
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(1) Tornadoes that cross state lines are counted in every state in which they touch down.
Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service.
Tornadoes And Related Deaths By State, 2015 (1)
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- Ranked by total number of tornadoes.
- States with the same number receive the same ranking.
- State had no tornadoes in 2015.
- The U.S. total will not match data used in other charts because it counts tornadoes that cross state lines.
Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service.
Tornadoes And Related Deaths In The United States, 1996-2015 (1)
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(1) Excludes Puerto Rico. A tornado that crosses state lines counts as one event.
Source: U.S. Department of Commerce, Storm Prediction Center, National Weather Service.
U.S. CONVECTIVE LOSS EVENTS, 1980-2015
(2015 $ billions)
us_convective_loss_events_80-15.gif
Source: © 2016 Munich Re, NatCatSERVICE; Property Claim Services (PCS®)*, a Verisk Analytics® business. As of January 2016.
U.S. TORNADO COUNT, 2015
us_torn_count_15.gif
Source: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Weather Service.