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Tornado Statistics - Windows to the Universe

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The Spring 2011 issue of The Earth Scientist is focused on modernizing seismology education. Thanks to IRIS, you can download this issue for free as a pdf. Print copies are available in our online store.
Tornadoes and tornado deaths, sorted by Fujita class.
Click on image for full size
Courtesy of University of Chicago

Tornado Stats

Most of the world's tornadoes occur in the United States. The area where most of them develop is called Tornado Alley. About 750 tornadoes strike the U.S. each year and about 100 people are killed by these storms. Most only last a few minutes and travel only a few miles, but some can last much longer and travel over 100 miles.

Some really severe thunderstorms can spawn more than one tornado. These are know as tornado families. They can form one after another or they can form in a line. Some really strong tornadoes even break into smaller ones.

Tornadoes are divided into groups according to how strong their winds are. Violent tornadoes don't happen very often, but they cause the most destruction and loss of life. Meteorologists have new equipment and new knowledge that allows them to forecast tornadoes earlier. With an earlier forecast, they can issue warnings and tell the public to take shelter. This had helped lower the death toll due to tornadoes. But, scientists don't know how to stop tornadoes so they can't easily reduce the damage caused my them.
Last modified May 17, 2007 by Jennifer Bergman.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF