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How to Measure Tornadoes: The EF Scale

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Tornado outside of Erie Kansas

Photo Credit
Amy Price

The EF Scale

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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)
 Wind SpeedWind Damage
F040-72 mph (64-116 km/h)Light Damage
F173-112 mph (117-180 km/h)Moderate Damage
F2113-157 mpg (181-253 km/h)Considerable Damage
F3158-207 mph (254-332 km/h)Severe Damage
F4208-260 mph (333-419 km/h)Devastating Damage
F5261-318 mph (420-512 km/h)Incredible Damage

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.

EF Scale
 Wind SpeedWind Damage
EF065-85 mph (105-137 km/h)Light Damage
EF186-110 mph (138-178 km/h)Moderate Damage
EF2111-135 mpg (179-218 km/h)Considerable Damage
EF3136-165 mph (219-266 km/h)Severe Damage
EF4166-200 mph (267-322 km/h)Devastating Damage
EF5over 200 mph (over 322 km/h)Incredible Damage
tornado-scale_full_width.png, f scale and ef scale

See how to predict a tornado.

About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann