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Enhanced F Scale For Tornado Damage |
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Written by NOAA NWS SPC
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Thursday, 08 May 2008 |
Enhanced F Scale for Tornado Damage
An update to the the original F-scale by a team of meteorologists and wind engineers, was implemented in the U.S. on 1 February 2007.
| 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.
Enhanced F Scale Damage Indicators
| NUMBER (Details Linked) |
DAMAGE INDICATOR |
ABBREVIATION |
| 1 |
Small barns, farm outbuildings |
SBO |
| 2 |
One- or two-family residences |
FR12 |
| 3 |
Single-wide mobile home (MHSW) |
MHSW |
| 4 |
Double-wide mobile home |
MHDW |
| 5 |
Apt, condo, townhouse (3 stories or less) |
ACT |
| 6 |
Motel |
M |
| 7 |
Masonry apt. or motel |
MAM |
| 8 |
Small retail bldg. (fast food) |
SRB |
| 9 |
Small professional (doctor office, branch bank) |
SPB |
| 10 |
Strip mall |
SM |
| 11 |
Large shopping mall |
LSM |
| 12 |
Large, isolated ("big box") retail bldg. |
LIRB |
| 13 |
Automobile showroom |
ASR |
| 14 |
Automotive service building |
ASB |
| 15 |
School - 1-story elementary (interior or exterior halls) |
ES |
| 16 |
School - jr. or sr. high school |
JHSH |
| 17 |
Low-rise (1-4 story) bldg. |
LRB |
| 18 |
Mid-rise (5-20 story) bldg. |
MRB |
| 19 |
High-rise (over 20 stories) |
HRB |
| 20 |
Institutional bldg. (hospital, govt. or university) |
IB |
| 21 |
Metal building system |
MBS |
| 22 |
Service station canopy |
SSC |
| 23 |
Warehouse (tilt-up walls or heavy timber) |
WHB |
| 24 |
Transmission line tower |
TLT |
| 25 |
Free-standing tower |
FST |
| 26 |
Free standing pole (light, flag, luminary) |
FSP |
| 27 |
Tree - hardwood |
TH |
| 28 |
Tree - softwood |
TS |
A 95 page PDF file explaining the development and makeup of the Enhanced F-scale now is available, both here and from the Texas Tech server.
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Last Updated ( Thursday, 08 May 2008 )
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