Estimation of wind speeds based upon the damages caused by tornadoes to buildings and structures

The Fujita scale (F-Scale) was devised in 1971 by professor T. Theodore Fujita of the University of Chicago to classify U.S. tornadoes in 12 categories bridging the gap between the force 12 of the Beaufort wind speed scale and Mach-1 number (ratio of the speed of an object to the speed of sound). Only the first six categories (F0- F5) are used as the maximum wind speeds of tornadoes are not expected to exceed the 512 km/h (277 kt), upper limit of F5

Reference: 1987 - Fujita, T. Theodore, "U.S. Tornadoes Part 1 70-Year Statistics," Satellite and Mesometeorology Research Project (SMRP) Research Paper Number 218, University of Chicago, 122 pp.

SAFFIR-SIMPSON SCALE

INFORMATION AND DOCUMENTS

REPORT

METEOMAR

FORECASTS

CHARTS

CLIMATE

OBSERVATIONS

WEBCAM

THE FUJITA TORNADO SCALE

scale	Tornado	Wind speed	Typical effects
F0	GALE	64-116 km/h	Light damages: some damage to chimneys - breaking of twigs and branches off trees - shallow-rooted trees push over - damages to signboards - some windows broken (hurricane wind speed begins at 117 km/h)
F1	MODERATE	117-180 km/h	Moderate damages: tiles peeled off roofs - mobile homes pushed off foundations or overturned - outbuildings demolished - moving autos pushed off the roads - trees snapped or broken
F2	SIGNIFICANT	181-253 km/h	Considerable damages: roofs torn off frame houses - mobile homes demolished - frame houses with weak foundations lifted and moved - boxcars pushed over - large trees snapped or uprooted - light-object missiles generated.
F3	SEVERE	254-332 km/h	Severe damages: roofs and some walls torn off well-constructed houses - trains overturned - most trees in forests uprooted - heavy cars lifted off the ground and thrown - weak pavement blown off roads
F4	DEVASTATING	333-419 km/h	Devastating damages: well constructed homes leveled - structures with weak foundations blown off some distance - cars thrown and disintegrated - large missiles generated - trees in forest uprooted and carried some distance away
F5	INCREDIBLE	420-512 km/h	Incredible damages: strong frame houses lifted off foundations and carried considerable distance to disintegrate - automobile-sized missiles fly through the air in excess of 100 m - trees debarked - incredible phenomena will occur