Classifying Tornadoes

Tornadoes are classified by their wind speeds using a scale defined by Dr. Ted Fujita at the University of Chicago. The Fujita, or F, scale ranges from 0 to 5 for known tornadoes. In May 1999, an F5 tornado in Oklahoma produced the fastest wind speeds ever recorded on Earth—318 mph!

The Fujita scale actually has no upper limit, although tornadoes with F6 winds or above have never been recorded.

F Scale Wind Speed Effects
F0 up to 72 mph light damage
F1 73 to 112 mph moderate damage
F2 113 to 157 mph considerable damage
F3 158 to 206 mph severe damage
F4 207 to 260 mph devastating damage
F5 261 to 318 mph incredible damage
F6 - upward over 318 mph unknown (catastrophic damage probable)