The Fujita Scale for Tornado Damage

Fujita Tornado Damage Scale
Developed in 1971 by T. Theodore Fujita of the University of Chicago.
Scale Wind Estimate,*          mph (km/hr)                         Typical Damage
F0                                           < 73 (117)                          Light damage. Some damage to chimneys;                                                                                                branches broken off trees;
                                                                                          shallow-rooted trees pushed over;
                                                                                          sign boards damaged.
F1                                          73-112 (117-180)               Moderate damage. Peels surface off roofs;                                                                                               mobile homes pushed off foundations or                                                                                                   overturned; moving autos blown off roads.
F2                                          113-157 (181-253)            Considerable damage. Roofs torn off frame                                                                                               houses; mobile homes demolished;
                                                                                          boxcars overturned; large trees snapped
                                                                                       or uprooted; light-object missiles generated;
                                                                                         cars lifted off ground.
F3                                          158-206 (254-332)          Severe damage. Roofs and some walls torn off                                                                                         well-constructed houses; trains overturned;
                                                                            most trees in forest uprooted; heavy cars lifted off the
                                                                                                       ground and thrown.
F4                                         207-260 (333-418)        Devastating damage. Well-constructed houses                                                                                 leveled; structures with weak foundations blown away
                                                                        some distance; cars thrown and large missiles generated.
F5                                        261-318 (419-512)           Incredible damage. Strong frame houses leveled
                                                                                           off foundations and swept away;
                                                                                        automobile-sized missiles fly through the
                                                                                          air in excess of 100 meters (109 yds);
                                                                               trees debarked; incredible phenomena will occur.


*IMPORTANT NOTE ABOUT F-SCALE WINDS:
 Do not use F-scale winds literally. These precise wind speed numbers are actually guesses and have never been scientifically verified. Different wind speeds may cause similar-looking damage from place to place — even from building to building. Without a thorough engineering analysis of tornado damage in any event, the actual wind speeds needed to cause that damage are unknown. Enhanced Fujita Scale (EF) for Tornado Damage.


An update to the original Fujita Scale by a team of meteorologists and wind engineers, was implemented in the U.S. on February 1, 2007. The Enhanced F-scale still is a set of wind estimates (not measurements) based on damage. It uses three-second gusts estimated at the point of damage based on a judgment of 8 levels of damage to 28 indicators. These estimates vary with height and exposure. Important: The 3-second gust is not the same wind as in standard surface observations. Standard measurements are taken by weather stations in open exposures, using a directly measured, “one minute mile” speed.





http://www.spc.noaa.gov/faq/tornado/
NOAA/National Weather Service
National Centers for Environmental Prediction
Storm Prediction Center
120 David L. Boren Blvd.
Norman, OK 73072 U.S.A.