"Fujita Tornado Damage Scale"

"Developed in 1971 by T. Theodore Fujita of the University of Chicago"

SCALE	WIND ESTIMATE (MPH)	TYPICAL DAMAGE
F0	<73	Light Damage. Some damage to chimneys; branches broken off trees; shallow-rooted trees pushed over; sign boards damage
F1	73-112	Moderate Damage. Peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos blown off the road
F2	113-157	Considerable Damage. Roofs torn off frame houses; mobile homes demolished; boxcars overturned; large trees snapped or uprooted; light weighted objects become missiles; cars lifted off the ground
F3	158-206	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	207-260	Devastating damage. Well-constructed houses leveled; structures with weak foundations blown away some distance; cars thrown and large missiles generated.
F5	261-318	Incredible damage. Strong frame houses leveled 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.

"IMPORTANT NOTE ABOUT F-SCALE WINDS":

Do not use F-scale winds literally. These precise wind speed numbers are actually estimates of wind speeds after assessing the amount of and extend of damage to structures in/near the path of a tornado. These wind speeds have never been scientifically verified. Different wind speeds may cause similar-looking damage on different structures due to the quality of construction. Without a thorough engineering analysis of tornado damage in any event, the actual wind speeds needed to cause that damage are unknown."