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50 Amazing Tornado Facts

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Terrible Tornadoes

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A still from a YouTube video that caught an F5 tornado near Elie, Manitoba in Canada on June 22, 2007. (Image credit: YouTube/Justin Hobson)

These swirling vortices are one of the most destructive forces Mother Nature dishes out. Many aspects of tornado formation are still not well-understood, but there are some basic facts that meteorologists have established from decades of observation. Here, learn more about tornadoes, how we define them and which have been the biggest, deadliest and costliest twisters in recorded history.

Violent storms

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Storm chasing scientists ride toward a tornado in Wyoming, just across the border from Nebraska, during the VORTEX2 mission in 2009. (Image credit: UCAR.)

Tornadoes are the most violent of the storms the atmosphere produces, according to the National Severe Storms Laboratory (NSSL) in Norman, Okla.

Tornado defined

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A tornado in Dimmitt, Texas, photographed on June 2, 1995. (Image credit: NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory (NSSL))

A tornado is defined by the NSSL as "a narrow, violently rotating column of air that extends from the base of a thunderstorm to the ground."

A big target

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A map made by John Nelson, the user experience and mapping manager for IDV Solutions, shows the paths of tornadoes that struck the United States between 1950 and 2006. The brightness of the line corresponds to the strength of the tornado. (Image credit: John Nelson, IDV Solutions.)

About 1,200 tornadoes hit the United States each year, according to the NSSL.

No place exempt

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An EF1 tornado touched down in the North Riverdale section of the Bronx in July 2010. (Image credit: NYC.gov.)

Tornadoes have been observed in all 50 U.S. states.

Open season

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A tornado near Mayfield, Okla., on May 16, 1977. (Image credit: NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory (NSSL))

Unlike for hurricanes, there is no defined tornado season and no official tornado season forecast.

Prime time

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A tornado over the plains of Kansas on May 23, 2008, when an outbreak of tornadoes hit from eastern Colorado to Oklahoma from May 23-24. (Image credit: Sean Waugh NOAA/NSSL)

The main time for tornado activity is during the spring, generally picking up in March and then hitting a peak between May and June.

Early arrival

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Damage caused by a tornado that struck Attala County, Miss., on Jan. 1, 2011. (Image credit: NWS Jackson)

The earliest tornado in the year in the modern record occurred at 12:02 a.m. CST on Jan. 1, 2011, in Attala County, Miss.

Late comer

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Damage caused by a tornado that struck Marengo County, Ala., on Feb. 15, 2003. (Image credit: NWS Birmingham, AL.)

The latest that the first tornado of the year has ever been recorded was on Feb. 15, 2003, in Marengo County, Ala.

Time to watch out

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A map of the tornadoes that struck the United States in May 2003. (Image credit: NOAA/Storm Prediction Center)

May is historically the most active month for tornadoes. The record holder for any May is May 2003, with 543 confirmed tornadoes.

Active April

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A map of tornado reports across the country from April 1-30, 2011, based on NOAA data. (Image credit: SPC/NOAA)

The most active tornado month on record is April 2011, which had 758 tornadoes, according to National Oceanic and Atmospheric Administration records.

Andrea Thompson
Andrea Thompson
Live Science Contributor

Andrea Thompson is an associate editor at Scientific American, where she covers sustainability, energy and the environment. Prior to that, she was a senior writer covering climate science at Climate Central and a reporter and editor at Live Science, where she primarily covered Earth science and the environment. She holds a graduate degree in science health and environmental reporting from New York University, as well as a bachelor of science and and masters of science in atmospheric chemistry from the Georgia Institute of Technology.

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