Page:1998-1999 Tornadoes and a Long-Term U.S. Tornado Climatology.pdf/24

Figure 10

U.S.A. Annual Tornado Count, 1950–1999
Very Strong Through Violent Tornadoes

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National Climatic Data Center, NOAA

Annual total number of very strong through violent (F3–F5) tornadoes, which are defined as having estimated wind speeds from 158 to 318 mph. The Fujita tornado classification scale was implemented in 1971. Prior to 1971, these data are based on storm damage reports.

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