Tornado Activity in the U.S. 1950-2007

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This Demonstration maps and plots frequencies of all U.S. tornadoes and tornado-related fatalities and injuries from 1950 to 2007.

Contributed by: Josh Lietz (March 2011)
Open content licensed under CC BY-NC-SA



In "map" view, the relative number of events (tornadoes, fatalities, or injuries) for any specific state determines the intensity of its color. For example, the states with a higher number of tornadoes in the given time period will be more intensely red, while states with a lower number of tornadoes will be less intense or white. Note that the intensity of color for any state is based on a relative comparison to other states for that map selection only. In other words, a deep red for Mississippi when viewing fatalities in January does not necessarily indicate a higher number of fatalities than Illinois in April, which is a less intense red. Instead, it only indicates that Mississippi has a high number of fatalities in January compared to every other state in January.

In "plot" view, note that the general increase in overall tornado frequency since 1950 may be due in part to greater numbers of local spotter networks and radar.

All data was gathered from the Tornado History Project.

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