Fujita Tornado Damage Scale
Category F0: Light Damage (less than 73 mph); Some damage to chimneys; branches broken off trees; shallow-rooted trees pushed over; sign boards damaged.
Category F1: Moderate Damage (73 to 112 mph); Peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos blown off road.
Category F2: Considerable Damage (113 to157 mph); Roofs torn off frame houses; mobile homes demolished; boxcars overturned; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground.
Category F3: Severe Damage (158 to 206 mph); Roofs and some walls torn off well-constructed houses; trains overturned; most trees uprooted; heavy cars lifted off ground and thrown.
Category F4: Devastating Damage (207 to 260 mph); Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.
Category F5: Incredible Damage (261 to 318 mph); Strong-frame houses lifted off foundations and swept away; automobile sized missiles fly through the air in excess of 100 meters (109 yards); trees debarked; incredible phenomena will occur.