Damage from the 1999 F5 tornado that struck Moore, Oklahoma. Photo courtesy NOAA.
Dr. T. Theodore Fujita developed the Fujita Tornado Damage Scale (F-Scale) to provide estimates of tornado strength based on damage surveys. Since it's practically impossible to make direct measurements of tornado winds, an estimate of the winds based on damage is the best way to classify a tornado. The new Enhanced Fujita Scale (EF-Scale) addresses some of the limitations identified by meteorologists and engineers since the introduction of the Fujita Scale in 1971. The new scale identifies 28 different free standing structures most affected by tornadoes taking into account construction quality and maintenance. The range of tornado intensities remains as before, zero to five, with 'EF-0' being the weakest, associated with very little damage and 'EF-5' representing complete destruction, which was the case in Greensburg, Kansas on May 4th, 2007, the first tornado classified as 'EF-5'. The EF scale was adopted on February 1, 2007.
The Storm Prediction Center has a brief description of the Enhanced Fujita Scale.
|EF-0 (65-85 mph)
||F0 (65-73 mph)
||Light damage. Peels surface off some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over.
|EF-1 (86-110 mph)
||F1 (73-112 mph)
||Moderate damage. Roofs severely stripped; mobile homes overturned or badly damaged; loss of exterior doors; windows and other glass broken.
||F2 (113-157 mph)
||Considerable damage. Roofs torn off well-constructed houses; foundations of frame homes shifted; mobile homes completely destroyed; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground.
|EF-3 (136-165 mph)
||F3 (158-206 mph)
||Severe damage. Entire stories of well-constructed houses destroyed; severe damage to large buildings such as shopping malls; trains overturned; trees debarked; heavy cars lifted off the ground and thrown; structures with weak foundations blown away some distance.
|EF-4 (166-200 mph)
||F4 (207-260 mph)
||Devastating damage. Whole frame houses Well-constructed houses and whole frame houses completely leveled; cars thrown and small missiles generated.
|EF-5 (>200 mph)
||F5 (261-318 mph)
||Incredible damage. Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 m (109 yd); high-rise buildings have significant structural deformation; incredible phenomena will occur.
|EF No rating
||F6-F12 (319 mph to speed of sound)
||Inconceivable damage. Should a tornado with the maximum wind speed in excess of EF-5 occur, the extent and types of damage may not be conceived. A number of missiles such as iceboxes, water heaters, storage tanks, automobiles, etc.will create serious secondary damage on structures.
Example of EF-0 damage. Photo courtesy NWS.
Example of EF-1 damage. Photo courtesy NWS.
Example of EF-2 damage. Photo courtesy NWS.
Example of EF-3 damage. Photo courtesy NWS.
Example of EF-4 damage. Photo courtesy NWS.
Example of EF-5 damage. Photo courtesy NWS.
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