The Tornado F-Scale
The above two pie charts
are from one of the best sources for tornado information available,
THE Tornado
Project (Visit
them by clicking on the link)
| The Power of Tornadoes | ||
| Classification | Speed/Width | Damage |
| F Doubtful Tornado | less than 40 mph | Winds typically break twigs off trees. Little damage expected. |
| F0 Very Weak Tornado | 40-72 mph | Damages chimneys or TV antennae; breaks branches off trees; pushes over shallow-rooted trees; old trees with hollow inside break or fall; sign boards damaged. |
| F1 Weak Tornado | 73-112 mph | Peels surface off roofs; windows broken; trailer houses pushed or overturned; trees on soft ground uprooted; some trees snapped; moving autos pushed off the road. |
| F2 Strong Tornado | 113-157
mph
100-200 yds wide |
Roof torn off frame houses leaving strong upright walls standing; weak structure or outbuildings demolished; trailer houses demolished; railroad boxcars pushed over, large trees snapped or uprooted; light-object missiles generated; cars blown off highway; block structures and walls badly damaged. |
| F3 Severe Tornado | 158-206
mph
200yds-1/4 mi across |
Roofs and some walls torn off well-constructed fame houses; some rural buildings completely demolished or flattened; trains overturned; steel framed hangar-warehouse type structures torn; cars lifted off ground and may roll some distance; most trees in a forest uprooted, snapped, or leveled; block structures often leveled. |
| F4 Devastating Tornado | 207-260
mph
1/4-1 mile across |
Well constructed frame houses leveled, leaving piles of debris; structures with weak foundation lifted, torn, and blown off some distance; trees debarked by small flying debris; sandy soil eroded and gravels fly in high winds; cars thrown some distances or rolled considerable distances. |
| F5 Incredible Tornado | 261-318
mph
1/2-2 miles across |
Strong frame houses lifted clear off foundation and carried considerable distance; steel reinforced concrete structures badly damaged; automobile-sized missiles fly through the distance of 100 yards or more; trees debarked completely. |
| F6 Inconceivable Tornado | 319
mph
to Mach 1 |
The effects are inconceivable. There is reason to believe that there is a "thermodynamic speed limit," and winds faster than 300 mph cannot occur in a tornado. |
| The
Fujita Scale, named for Dr. T.T. (Ted) Fujita, is a classification model
that equates tornado wind speeds with potential damage:
F-6 is impossible and not classified by the National Weather Service. |
||
|
University of Nebraska-Lincoln High Plains Climate Center |