The Fujita Scale

This is the Fujita Scale. It measures the miles per hour and the damage it causes.

Fujita Classification
Wind speed (mph)
Damage
F - 0
42 - 72
Light
F - 1
73 - 112
Moderate
F - 2
113 - 157
Considerable
F - 3
158 - 206
Severe
F - 4
207 - 260
Devastating
F - 5
261 - 318
Incredible

There is a F-6, which is 319 mph.-Mach 1, but has never been scientificly proven to be possible.

Facts about different types of Tornadoes :

Tornado type
Fujita Ranking
% of Tornadoes
Lifetime
% of Tornado Deaths
Weak
F0-F1
69%
1 - 10+ Minutes
Less than 5%
Strong
F2-F3
29%
20+ Minutes
30%
Violent
F4-F5
2%
1+ Hours
70%