Tornado Intensity

The Fujita-Pearson Tornado Intensity Scale (or "F-Scale") is used by meteorologists to measure tornado wind speeds. The scale was named after the two men who developed it: Dr. Theodore Fujita, and Allan Pearson, head of the Forecast Center in Kansas City.

F-SCALE	WINDS	CHARACTER OF DAMAGE	RELATIVE FREQUENCY
F0 (weak)	40-72 mph	LIGHT DAMAGE: Some damage to chimneys, TV antennas, roof shingles displaced. Small branches broken on trees.	29%
F1 (weak)	73-112 mph	MODERATE DAMAGE: Roof decking removed, carports overturned, some trees uprooted, automobiles overturned. Unanchored homes sliding.	40%
F2 (strong)	113-157 mph	CONSIDERABLE DAMAGE: Roofs blown off homes leaving strong walls standing. Sheds and other outbuildings demolished, unanchored mobile homes overturned, block structure walls collapsed, roofs peeled back. Small wood missiles observed.	24%
F3 (strong)	158-206 mph	SEVERE DAMAGE: Exterior walls and roofs blown off homes. Metal buildings collapsed or are severely damaged. Forests are flattened. Most block structures collapsed.	6%
F4 (violent)	207-260 mph	DEVASTATING DAMAGE: Few walls, if any, standing in well-built homes. Pile of debris on foundation, large steel and concrete missiles thrown far distances.	2%
F5 (violent)	261-318 mph	(RARE) INCREDIBLE DAMAGE: Homes on slabs levelled with debris removed. Schools, motels and other marginally engineered buildings have considerable damage with exterior walls and roofs gone. Top stories demolished.	less than 1%

Note that less than 3% of all tornadoes become violent, with winds that can level brick homes.

Introductory Information | Safety Information | General Glossary | Tornado Intensity Scale
Warning Definitions | Severe Event Location Codes | Tornado Statistics Listed by State (1950-1994)
1995 Killer Tornadoes | Storm Chaser's Guide

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