The Fujita Scale
|
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.
|
|
F6
|
Inconceivable tornado
|
319-379 mph
|
These winds are very unlikely. The small area of damage they
might produce would probably not be recognizable along with the mess produced
by F4 and F5 wind that would surround the F6 winds. Missiles, such as cars
and refrigerators would do serious secondary damage that could not be directly
identified as F6 damage. If this level is ever achieved, evidence for it
might only be found in some manner of ground swirl pattern, for it may
never be identifiable through engineering studies
|
NOTE: The Fujita Scale is based on damage, not the appearance of
the funnel.