The Fujita Scale

 

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. 

F-Scale Number
Intensity Phrase
Wind Speed
Type of
Damage Done

F0Gale tornado65-85 mphSome damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.
F1Moderate tornado86-110 mphThe lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.
F2Significant tornado111-135 mphConsiderable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.
F3Severe tornado136-165 mphRoof and some walls torn off well constructed houses; trains overturned; most trees in fores uprooted
F4Devastating tornado166-200 mphWell-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.
F5Incredible tornado>200 mphStrong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-inforced concrete structures badly damaged.

 

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