Fujita Scale

Name

Characteristics of Damage

F-1

40 mph speed corresponds to Beaufort 8 or "Fresh Gale". Beaufort specification for use on land is "Breaks twigs off trees". Little damage is expected.

F0

Light damage: This speed range corresponds to Beaufort 9 through 11. Some damage to chimneys or TV antennae; breaks branches off trees; pushes over shallow rooted trees; old trees with hollow inside break or fall; sign boards damaged.

F1

Moderate damage: 73 mph is the beginning of hurricane windspeed or Beaufort 12. Peels surface off roofs; windows broken; trailer houses [mobile homes] pushed off foundations or overturned; garages attached to buildings may be destroyed; trees on soft ground uprooted; some trees snapped; moving autos pushed off the road.

F2

Considerable damage: Roof torn off frame houses leaving strong upright walls standing; weak structure or outbuildings demolished; trailer houses demolished; railroad boxcars pushed over; large trees snapped or uprooted; light-object missiles generated; cars blown off highway; block structures and walls badly damaged.

F3

Severe damage: Roofs and some walls torn off well-constructed frame houses; some rural buildings completely demolished or flattened; trains overturned; steel-framed hanger-warehouse type structures torn; heavy cars lifted off the ground and may roll some distance; most trees in a forest uprooted, snapped, or levelled; block structures often levelled.

F4

Devastating damage: Well-constructed frame houses levelled, leaving piles of debris; structures with weak foundations lifted, torn and blown off some distance; trees debarked by small flying debris; sandy soil eroded and gravels fly in high winds; cars thrown some distances or rolled considerable distance finally to disintegrate; large missiles generated.

F5

Incredible damage: Strong frame houses lifted clear off foundation and carried considerable distance to disintegrate; steel-reinforced concrete structures badly damaged; automobile-sized missiles fly through the distance of 100 m or more; trees debarked completely; incredible phenomena can occur.

F6-12

The maximum wind speeds of tornadoes are not expected to reach F6 wind speeds. Should a tornado with the maximum windspeed in excess of F 6 occur, the extent and type of damage may not be conceived. A number of missiles such as iceboxes, water heaters, storage tanks, automobiles etc. will fly through a long distance, creating serious secondary damage on structures. Assessment of tornadoes in these categories is feasible only through detailed survey involving engineering and aerodynamical calculations as well as meteorological models of tornadoes.