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) |
