Fujita Tornado Scale

Fujita Tornado Scale
F0 - F1

Weak Tornado
F2 - F3

Strong Tornado
F4 - F5

Violent Tornado

F045-78 mph Gale tornado Light damage. Some damage to chimneys; break branches off trees; push over shallow-rooted trees; damage sign boards.
F1 79-117 mph Moderate tornado Moderate damage. The lower limit is the beginning of hurricane wind speed;peel surface off roofs; mobile homes pushed off foundations or overturned;moving autos pushed off the roads.
F2 118-161 mph Significant tornado Considerable damage. Roofs torn off frame houses; mobile homes demolished;boxcars pushed over; large trees snapped or uprooted; light-object missilesgenerated.
F3 162-209 mph Severe tornado. 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 210-261 mph Devastating tornado Devastating damage. Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.
F5 262-317 mph Incredible tornado. Incredible damage. Strong frame houses lifted off foundations and carried considerable distance to disintegrate; automobile sized missiles fly through the air in excess of 100 meters(109 yds); trees debarked; incredible phenomena will occur.
F6 318 mph - The maximum wind speeds of tornadoes are not expected to reach the F6 wind speeds.

Enhanced F Scale for Tornado Damage

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

Damage Indicators and Degrees of Damage

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.

DI No. Damage Indicator (DI) Degrees of Damage (DOD)
1 Small Barns or Farm Outbuildings (SBO) 8
2 One- or Two-Family Residences (FR12) 10
3 Manufactured Home – Single Wide (MHSW) 9
4 Manufactured Home – Double Wide (MHDW) 12
5 Apartments, Condos, Townhouses [3 stories or less] (ACT) 6
6 Motel (M) 10
7 Masonry Apartment or Motel Building (MAM) 7
8 Small Retail Building [Fast Food Restaurants] (SRB) 8
9 Small Professional Building [Doctor’s Office, Branch Banks] (SPB) 9
10 Strip Mall (SM) 9
11 Large Shopping Mall (LSM) 9
12 Large, Isolated Retail Building [K-Mart, Wal-Mart] (LIRB) 7
13 Automobile Showroom (ASR) 8
14 Automobile Service Building (ASB) 8
15 Elementary School [Single Story; Interior or Exterior Hallways] (ES) 10
16 Junior or Senior High School (JHSH) 11
17 Low-Rise Building [1–4 Stories] (LRB) 7
18 Mid-Rise Building [5–20 Stories] (MRB) 10
19 High-Rise Building [More than 20 Stories] (HRB) 10
20 Institutional Building [Hospital, Government or University Building] (IB) 11
21 Metal Building System (MBS) 8
22 Service Station Canopy (SSC) 6
23 Warehouse Building [Tilt-up Walls or Heavy-Timber Construction] (WHB) 7
24 Electrical Transmission Lines (ETL) 6
25 Free-Standing Towers (FST) 3
26 Free-Standing Light Poles, Luminary Poles, Flag Poles (FSP) 3
27 Trees: Hardwood (TH) 5
28 Trees: Softwood (TS) 5

'Mr. Tornado,' Ted Fujita, dies at 78

Tetsuya Theodore Fujita in the late 1980's. (AP file photo).
CHICAGO, Thursday, Nov. 19, 1998 - Tetsuya Theodore "Ted" Fujita, a University of Chicago meteorologist who devised the standard for measuring the strength of tornadoes and discovered microbursts and their link to plane crashes, has died at 78.

Fujita, known as "Mr. Tornado" after developing the international standard for measuring tornado severity, died Thursday after a lengthy illness.

Fujita discovered microbursts -- sudden, severe downdrafts from thunderstorms that can result in 150 mph winds on or near the ground -- after studying the starburst patterns of trees uprooted by tornadoes.

Ted Fujita shown with his tornado simulator in this file photo, date unknown (AP).

He blamed a microburst for the 1975 Eastern Airlines Flight 66 crash at New York's Kennedy Airport. The discovery, controversial for years before it became accepted among meteorologists, led to installation of Doppler radar at airports to improve safety.

Fujita did not trust computers to help conduct his analyses, preferring to do it himself, Chicago meteorologist Duane Stiegler said.

"He used to say that the computer doesn't understand these things," Stiegler said.

Born October 23, 1920, in Kitakyushu City, Japan, Fujita earned a bachelor's degree in mechanical engineering in 1943 from Meiji College of Technology and a doctoral degree from Tokyo University in 1953.

In 1953, he joined the University of Chicago as a research associate in the meteorology department. He held a number of positions during his career, most recently working in the Wind Research Laboratory.

By The Associated Press

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