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.

NUMBER OF TORNADOES AND RELATED DEATHS PER MONTH, 2013

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

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TORNADOES AND RELATED DEATHS IN THE UNITED STATES, 1993-2013 (1)

Year Tornadoes Deaths Year Tornadoes Deaths Year Tornadoes Deaths
1993 1,173 33 2000 1,071 40 2007 1,098 81
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

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

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

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