Enhanced Fujita Tornado Damage Scale

Enhanced F Scale for Tornado Damage

An update to the the original F-scale by a team of meteorologists and wind engineers, 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 is available here.

Enhanced F Scale for Tornado Damage

An update to the the original F-scale by a team of meteorologists and wind engineers, implemented in the U.S. on 1 February 2007.

Enhanced F Scale Damage Indicators

Back to The Online Tornado FAQ

Enhanced F-scale Website

Formal BAMS article on "Tornado Intensity Estimation" covering F and EF scale history and issues
SPC Home Page

SPC Home Page

Enhanced F Scale for Tornado Damage

An update to the the original F-scale by a team of meteorologists and wind engineers, implemented in the U.S. on 1 February 2007.

Enhanced F Scale Damage Indicators

Back to The Online Tornado FAQ

Enhanced F-scale Website

Formal BAMS article on "Tornado Intensity Estimation" covering F and EF scale history and issues SPC Home Page

SPC Home Page

Formal BAMS article on "Tornado Intensity Estimation" covering F and EF scale history and issues
SPC Home Page