Fujita Damage Intensity Scale
- F0 - F1 Weak Tornado
- F2 - F3 Strong Tornado
- F4 - F5 Violent Tornado
(F0) Gale tornado (40-72 mph)
- Light damage. Some damage to chimneys; break branches off trees; push
- over shallow-rooted trees; damage sign boards.
(F1) Moderate tornado (73-112 mph)
- Moderate damage. The lower limit is the beginning of hurricane wind speed;
- peel surface off roofs; mobile homes pushed off foundations or overturned;
- moving autos pushed off the roads.
(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
(F3) Severe tornado (158-206 mph)
- Severe damage. Roofs and some walls torn off well-constructed houses;
- trains overturned; most trees in forest uprooted; heavy cars lifted off the ground
- and thrown.
(F4) Devastating tornado (207-260)
- Devastating damage. Well-constructed houses leveled; structures with weak
- foundations blown off some distance; cars thrown and large missiles generated.
(F5) Incredible tornado (261-318 mph)
- Incredible damage. Strong frame houses lifted off foundations and carried
- considerable distance to disintegrate; automobile sized missiles fly through
- the air in excess of 100 meters(109 yds); trees debarked; incredible phenomena
- will occur.
(from J. Atmos. Sci., August 1981, pg 1517-1519)