Xenia Tornado

1974 Super Outbreak

Paths of the 148 tornadoes generated during the 1974 Super Outbreak.
Type	Tornado outbreak
Duration	April 3–4, 1974
Tornadoes confirmed	148 confirmed
Max rating1	F5 tornado
Duration of tornado outbreak2	≈18 hours
Damage	$3.5 billion (2005 USD)
Casualties	315 fatalities, 5,484 injuries
Areas affected	Midwestern and Southern United States, Ontario, Canada
1Most severe tornado damage; see Fujita scale 2Time from first tornado to last tornado

¹Most severe tornado damage; see Fujita scale

The 1974 Super Outbreak was the second-largest tornado outbreak on record for a single 24-hour period, just behind the 2011 Super Outbreak. It was also the most violent tornado outbreak ever recorded, with 30 F4/F5 tornadoes confirmed. From April 3 to April 4, 1974, there were 148 tornadoes confirmed in 13 U.S. states and the Canadian province of Ontario. In the United States, tornadoes struck Illinois, Indiana, Michigan, Ohio, Kentucky, Tennessee, Alabama, Mississippi, Georgia, North Carolina, Virginia, West Virginia, and New York. The entire outbreak caused more than $600 million (1974 USD) in damage in the United States alone, and extensively damaged approximately 900 sq mi (2,331 km²) along a total combined path length of 2,600 mi (4,184 km). At one point, as many as 15 separate tornadoes were ongoing at the same time.

The 1974 Super Outbreak remains one of the most outstanding severe convective weather episodes of record in the continental United States. The outbreak far surpassed previous and succeeding events in terms of severity, longevity, extent, and death toll, with the notable exception of the 2011 Super Outbreak, which lasted from April 25 to 28 and killed a total of 324 people.

A powerful spring-time low pressure system developed across the North American Interior Plains on April 1. While moving into the Mississippi and Ohio Valley areas, a surge of very moist air intensified the storm further while there were sharp temperature contrasts between both sides of the system. Officials at NOAA and in the National Weather Service forecast offices were expecting a severe weather outbreak on April 3, but not to the extent that ultimately occurred. Several F2 and F3 tornadoes had struck portions of the Ohio Valley and the South in a separate, earlier outbreak on April 1 and 2, which included three killer tornadoes in Kentucky, Alabama, and Tennessee. The town of Campbellsburg, northeast of Louisville, was hard-hit in this earlier outbreak, with a large portion of the town destroyed by an F3. Between the two outbreaks, an additional tornado was reported in Indiana in the early morning hours of April 3, several hours before the official start of the outbreak. On Wednesday, April 3, severe weather watches already were issued from the morning from south of the Great Lakes, while in portions of the Upper Midwest, snow was reported, with heavy rain falling across central Michigan and much of Ontario.