Tornadoes are classified according to the damage they cause. Through observational
studies, T. Theodore Fujita created the following scale in the late 1960's to
classify tornadoes. The scale correlates wind speeds with damage:
(F-0 is the weakest and F-5 the strongest).
Wind Estimate (MPH)
Some damage to chimneys; branches broken off trees;
shallow-rooted trees pushed over; sign boards damaged.
73 - 112
Peels surface off roofs; mobile homes pushed off foundations or
overturned; moving autos blown off roads.
113 - 157
Roofs torn off frame houses; mobile homes demolished; boxcars
overturned; large trees snapped or uprooted; light-object missiles
generated; cars lifted off ground.
158 - 206
Roofs and some walls torn off well-constructed houses; trains
overturned; most trees in forest uprooted; heavy cars lifted off the
ground and thrown.
207 - 260
Well-constructed houses leveled; structures with weak foundations
blown away some distance; cars thrown and large missiles generated.
261 - 318
Strong frame houses leveled off foundations and swept away;
automobile-sized missiles fly through the air in excess of 100
meters (109 yds); trees debarked;