| F-Scale Number |
Intensity Phrase |
Wind Speed |
Type of Damage Done |
| F0 |
Gale tornado |
40-72 mph |
Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards. |
| F1 |
Moderate tornado |
73-112 mph |
The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed. |
| F2 |
Significant tornado |
113-157 mph |
Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated. |
| F3 |
Severe tornado |
158-206 mph |
Roof and some walls torn off well constructed houses; trains overturned; most trees in forest uprooted |
| F4 |
Devastating tornado |
207-260 mph |
Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated. |
| F5 |
Incredible tornado |
261-318 mph |
Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-inforced concrete structures badly damaged. |