In 1971, a scale was started to help categorize the severity of tornados.
F-0: 40-72 mph, chimney damage, tree branches broken
F-1: 73-112 mph, mobile homes pushed off foundation or overturned
F-2: 113-157 mph, considerable damage, mobile homes demolished, trees
uprooted
F-3: 158-205 mph, roofs and walls torn down, trains overturned, cars
thrown
F-4: 207-260 mph, well-constructed walls leveled
F-5: 261-318 mph, homes lifted off foundation and carried considerable
distances, autos thrown as far as 100 meters
However, it was later learned that these wind speeds were inaccurate. The following material is taken from Wikipedia.
| Scale | Estimated wind speed* | Relative frequency | Potential damage | ||
| mph | km/h | ||||
| F0 | 40–72 | 64–116 | 38.9% | Light damage. Some damage to chimneys; branches broken off trees; shallow-rooted trees pushed over; sign boards damaged. |
|
| F1 | 73–112 | 117–180 | 35.6% | Moderate damage. The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed. |
|
| F2 | 113–157 | 181–253 | 19.4% | Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars overturned; large trees snapped or uprooted; light-object missiles generated. |
|
| F3 | 158–206 | 254–332 | 4.9% | 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 | 207–260 | 333–418 | 1.1% | Devastating damage. Well-constructed houses leveled; structures with weak foundations blown away some distance; cars thrown and large missiles generated. |
|
| F5 | 261–318 | 419–512 | Less than 0.1% | Incredible damage. Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 m (109 yd); trees debarked; steel reinforced concrete structures badly damaged; incredible phenomena will occur. |
|
| cale | Wind speed | Relative frequency | Potential damage | ||
| mph | km/h | ||||
| EF0 | 65–85 | 105–137 | 53.5% | Light damage.
Peels surface off some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over. Confirmed tornadoes with no reported damage (i.e. those that remain in open fields) are always rated EF0. |
|
| EF1 | 86–110 | 138–178 | 31.6% | Moderate damage.
Roofs severely stripped; mobile homes overturned or badly damaged; loss of exterior doors; windows and other glass broken. |
|
| EF2 | 111–135 | 179–218 | 10.7% | Considerable damage.
Roofs torn off well-constructed houses; foundations of frame homes shifted; mobile homes completely destroyed; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground. |
|
| EF3 | 136–165 | 219–266 | 3.4% | Severe damage.
Entire stories of well-constructed houses destroyed; severe damage to large buildings such as shopping malls; trains overturned; trees debarked; heavy cars lifted off the ground and thrown; structures with weak foundations blown away some distance. |
|
| EF4 | 166–200 | 267–322 | 0.7% | Devastating damage.
Well-constructed houses and whole frame houses completely leveled; cars thrown and small missiles generated. |
|
| EF5 | >200 | >322 | Less than 0.1% | Total destruction.
Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 m (109 yd); steel reinforced concrete structure badly damaged; high-rise buildings have significant structural deformation; incredible phenomena will occur. So far there have been two EF5 tornadoes recorded since the Enhanced Fujita Scale was introduced on February 1, 2007. The most recent one occurred in Parkersburg, Iowa on May 25, 2008 and leveled 1/2 the city. See Greensburg, Kansas tornado, Late-May 2008 tornado outbreak sequence |
|
In England, they use a different scale:
| TORRO intensity | Wind speeds | Tornado description |
Damage description |
|---|---|---|---|
| FC | - | Funnel cloud aloft (Not a tornado) | No damage to structures, unless on tops of tallest towers, or to radiosondes, balloons, and aircraft. No damage in the country, except possibly agitation to highest tree-tops and effect on birds and smoke. Record FC when not known to have reached ground level. A whistling or rushing sound aloft may be noticed. |
| T0 | 17 - 24 m/s 61 - 86 km/h 39 - 54 mph |
Light | Loose light litter raised from ground-level in spirals. Tents, marquees seriously disturbed; most exposed tiles, slates on roofs dislodged. Twigs snapped; trail visible through crops. |
| T1 | 25 - 32 m/s 87 - 115 km/h 55 - 72 mph |
Mild | Deckchairs, small plants, heavy litter becomes airborne; minor damage to sheds. More serious dislodging of tiles, slates, chimney pots. Wooden fences flattened. Slight damage to hedges and trees. |
| T2 | 33 - 41 m/s 116 - 147 km/h 73 - 92 mph |
Moderate | Heavy mobile homes displaced, light caravans blown over, garden sheds destroyed, garage roofs torn away, much damage to tiled roofs and chimney stacks. General damage to trees, some big branches twisted or snapped off, small trees uprooted. |
| T3 | 42 - 51 m/s 148 - 184 km/h 93 - 114 mph |
Strong | Mobile homes overturned / badly damaged; light caravans destroyed; garages and weak outbuildings destroyed; house roof timbers considerably exposed. Some of the bigger trees snapped or uprooted. |
| T4 | 52 - 61 m/s 185 - 220 km/h 115 - 136 mph |
Severe | Motor cars levitated. Mobile homes airborne / destroyed; sheds airborne for considerable distances; entire roofs removed from some houses; roof timbers of stronger brick or stone houses completely exposed; gable ends torn away. Numerous trees uprooted or snapped. |
| T5 | 62 - 72 m/s 221 - 259 km/h 137 - 160 mph |
Intense | Heavy motor vehicles levitated; more serious building damage than for T4, yet house walls usually remaining; the oldest, weakest buildings may collapse completely. |
| T6 | 73 - 83 m/s 260 - 299 km/h 161 - 186 mph |
Moderately- devastating |
Strongly-built houses lose entire roofs and perhaps also a wall; windows broken on skyscrapers, more of the less-strong buildings collapse. |
| T7 | 84 - 95 m/s 300 - 342 km/h 187 - 212 mph |
Strongly- devastating |
Wooden-frame houses wholly demolished; some walls of stone or brick houses beaten down or collapse; skyscrapers twisted; steel-framed warehouse-type constructions may buckle slightly. Locomotives thrown over. Noticeable de-barking of trees by flying debris. |
| T8 | 96 - 107 m/s 343 - 385 km/h 213 - 240 mph |
Severely- devastating |
Motor cars hurled great distances. Wooden-framed houses and their contents dispersed over long distances; stone or brick houses irreparably damaged; skyscrapers badly twisted and may show a visible lean to one side; shallowly anchored highrises may be toppled; steel-framed buildings buckled. |
| T9 | 108 - 120 m/s 386 - 432 km/h 241 - 269 mph |
Intensely- devastating |
Many steel-framed buildings badly damaged; skyscrapers toppled; locomotives or trains hurled some distances. Complete debarking of any standing tree-trunks. |
| T10 | 121 - 134 m/s 433 - 482 km/h 270 - 299 mph |
Super | Entire frame houses and similar buildings lifted bodily from foundations and carried some distances. Steel-reinforced concrete buildings may be severely damaged. |
| T11 | 300 - 320 mph | Destructive | Entire wood frame houses violently hurled from foundations, brick homes blown completely down; skyscrapers completely destroyed, wooden doors torn from storm cellars. Heavy irrepairable damage to steel reinforced concrete buildings. Capable of tearing asphalt from roads and grass from the ground. |
In early April 1974, a super cell with many tornados struck from Huntsville, Alabama to Xenia, Ohio. These are some of the pictures I took. Can you estimate what the F-scale value of this tornado was?
