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The EF Scale is the standard way to measure tornadoes based on wind damage.
The original Fujita Scale (or F Scale) was developed by Dr. Theodore Fujita. All tornadoes, and other severe local windstorms, were assigned a number according to the most intense damage caused by the storm.
The Fujita Scale (F Scale)
40-72 mph (64-116 km/h)
73-112 mph (117-180 km/h)
113-157 mpg (181-253 km/h)
158-207 mph (254-332 km/h)
208-260 mph (333-419 km/h)
261-318 mph (420-512 km/h)
The enhanced F Scale (EF Scale) was implemented in the United States on February 1, 2007. The EF scale uses three-second wind gust estimates based on a more detailed system for assessing damage, taking into account different building materials.