Storm Prediction Center - 1998 Tornado Summary

Source: U. Nebraska - Lincoln

Some Tornadoe disasters with high death tolls:
(Most were caused by a series of toradoes over 1 or 2 days) Most of these were F4 or F5 (See below).

Year	Date	Dead	States
1896	May 27	255	MO, IL
1899	June 12	117	WI
1908	Apr 24	143	LA-MS
1925	Mar. 18	695	MO, IL, IN
1936	Apr 5	216	MI
1936	Apr 6	203	GA
1947	Apr 9	181	TX-OK-KS
1953	June 8	115	MI
1953	May 11	114	TX
1965?		256	IN, OH, MI
1974 ?		315	11 states in the East, South, and Midwest. Largest number of tornadoes - 148
1985?		75	PA, OH
1994		42	AL, GA, NC
1997	Mar 1	27	AR, MS, TN
1998	Feb 22	42	FL
1998	Apr 8	41	AL, GA
1999	May 3	44	OK, KS
2002	Nov 10	34	OH, TN, AL
2003	May 4	33	KS, MO, IL
2008	Feb. 5-6	55	Tenn., Ark., Ala., Ky., Mo.
2008	May. 11	22	Mo., Okla., Ga.

The Top Ten US Killer Tornadoes at TornadoProject.com

The Frujita Scale of Torando Intensity:

F-Scale Number	Freq- uency	Intensity Phrase	Wind Speed	Type of Damage Done
F0	39%	Gale tornado	40-72 mph	Light Damage: Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.
F1	36%	Moderate tornado	73-112 mph	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	19%	Significant tornado	113-157 mph	Considerable damage: Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.
F3	4.9%	Severe tornado	158-206 mph	Severe Damage: Roof and some walls torn off well constructed houses; trains overturned; most trees in fores uprooted
F4	1.1%	Devastating tornado	207-260 mph	Devastating damage: Well-constructed houses leveled; structures with weak foundations blown off some distance; cars Thrown and large missiles generated.
F5	<0.1%	Incredible tornado	261-318 mph	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 meters; trees debarked; steel re-inforced concrete structures badly damaged.
F6	*	Inconceivable tornado	319-379 mph	These winds are very unlikely. The small area of damage They might produce would probably not be recognizable along with The mess produced by F4 and F5 wind That would surround The F6 winds. Missiles, such as cars and refrigerators would do serious secondary damage That could not be directly identified as F6 damage. If This level is ever achieved, evidence for it might only be found in some manner of ground swirl pattern, for it may never be identifiable Through engineering studies

Source: The Frujita Scale of Torando Intensity
See examples of damage at Wikipedia

US Tornadoes by state at TornadoProject.com
Tornadoes in the Past

Links:
The Frujita Scale of Torando Intensity
Beaufort, Fujita, and Mach number scales.
U.S. Severe Weather Meteorology And Climatology at University of Nebraska-Lincoln.