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Updated: 11:33 AM Mar 16, 2007 |
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The Enhanced Fujita Scale for tornado damage was implemented
in the U.S. on Feb. 1, 2007. Below is a chart that compares the new scale
to the old Fujita Scale.
| FUJITA SCALE | DERIVED EF SCALE | OPERATIONAL EF SCALE | ||||
| F Number | Fastest 1/4-mile (mph) | 3 Second Gust (mph) | EF Number | 3 Second Gust (mph) | EF Number | 3 Second Gust (mph) |
| 0 | 40-72 | 45-78 | 0 | 65-85 | 0 | 65-85 |
| 1 | 73-112 | 79-117 | 1 | 86-109 | 1 | 86-110 |
| 2 | 113-157 | 118-161 | 2 | 110-137 | 2 | 111-135 |
| 3 | 158-207 | 162-209 | 3 | 138-167 | 3 | 136-165 |
| 4 | 208-260 | 210-261 | 4 | 168-199 | 4 | 166-200 |
| 5 | 261-318 | 262-317 | 5 | 200-234 | 5 | Over 200 |
IMPORTANT NOTE ABOUT ENHANCED F-SCALE WINDS: The Enhanced F-scale
still is a set of wind estimates (not measurements) based on damage. Its
uses three-second gusts estimated at the point of damage based on a judgment of
8 levels of damage to the 28 indicators listed below. 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.
Source: http://www.spc.noaa.gov/faq/tornado/ef-scale.html
