How Many? A Dictionary of Units of Measurement
© Russ Rowlett and the University of North Carolina at Chapel Hill

Table of Contents
About the Dictionary
Using the Dictionary
Enhanced Fujita Tornado Intensity Scale

Effective February 1, 2007, the U.S. National Weather Service has revised the Fujita scale for estimating the strength of tornados. The new Enhanced F Scale estimates the strongest 3-second wind gust based on the degree of damage to one or more of 28 classes of trees or structures. Full information on the new scale is available here from the NWS Storm Prediction Center in Kansas City, Missouri.

EF Number
Maximum 3-second Gust (mi/h)
Maximum 3-second Gust (km/h) 
Maximum 3-second Gust (knots)

EF0
65-85
105-137
56-74

EF1
86-110
138-178
75-96

EF2
111-135
179-217
97-117

EF3
136-165
218-265
118-143

EF4
166-200
266-322
144-174

EF5
Over 200
Over 322
Over 174

 

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You are welcome to email the author (rowlett@email.unc.edu) with comments and suggestions.

All material in this folder is copyright © 2007 by Russ Rowlett and the University of North Carolina at Chapel Hill. Permission is granted for personal use and for use by individual teachers in conducting their own classes. All other rights reserved. You are welcome to make links to this page, but please do not copy the contents of any page in this folder to another site. The material at this site will be updated from time to time.

Posted January 10, 2000; checked and revised February 19, 2007.