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Tornado outbreak sequence of May 2004

Tornado outbreak sequence of May 2004
Radar image of the supercell that spawned the Hallam, Nebraska, tornado.
TypeTornado outbreak
DurationMay 21, 2004 (2004-05-21) – May 31, 2004 (2004-05-31)
Highest winds
Tornadoes
confirmed
389 (33 significant)
Max. rating1F4 tornado
Duration of
tornado outbreak2
11 days
Fatalities7 fatalities, 123 injuries
Damage$175 million (May 22)
$65 million (May 29–31)
Areas affectedCentral, Southern, and Eastern United States, Ontario

1Most severe tornado damage; see Fujita scale
2Time from first tornado to last tornado

The tornado outbreak sequence of May 2004 was a series of tornado outbreaks that affected much of southern Ontario, the Central and Southern United States from east of the Rockies to the Mid-Atlantic States from May 21 to May 31, 2004. Particularly hard hit were the central Plains from Missouri to Iowa and the Ohio Valley. The Central Plains were hit by two significant outbreaks on May 22 and May 24, the first outbreak of which produced a very large and violent tornado in Hallam, Nebraska. The Ohio Valley was affected by one of the largest tornado outbreaks ever during the Memorial Day weekend on May 29–30.

Seven people were killed in four states during the entire event. In all, 389 tornadoes were confirmed over an 11-day period – close to the number of tornadoes in the May 2003 tornado outbreak sequence which affected more or less the same area. However, the 2003 outbreak sequence produced several more destructive and violent tornadoes and had a much higher death toll than in May 2004.