The 1974 Super Outbreak was the second-largest tornado outbreak on record for a single 24-hour period, just behind the 2011 Super Outbreak.
The 2011 Super Outbreak was the largest, costliest and one of the deadliest tornado outbreaks ever recorded, taking place along the Southern, Midwestern, and Northeastern United States and leaving catastrophic destruction in its wake.
A tornado outbreak is the occurrence of multiple tornadoes spawned by the same synoptic scale weather system.
Tornado Super Outbreak of 1974: Day of the Killer Tornadoes 1978 US DCPA by Jeff Quitney
It was also the most violent tornado outbreak ever recorded, with 30 F4/F5 tornadoes confirmed.
Day of the Killer Tornadoes - 1978 by caholla
From April 3 to 4, 1974, there were 148 tornadoes confirmed in 13 U.S. states and the Canadian province of Ontario.
Ontario is one of the 13 provinces and territories of Canada and is located in east-central Canada.
A U.S. state is a constituent political entity of the United States.
In the United States, tornadoes struck Illinois, Indiana, Michigan, Ohio, Kentucky, Tennessee, Alabama, Mississippi, Georgia, North Carolina, Virginia, West Virginia, and New York.
Mississippi is a state located in the southern region of the United States, with part of its southern border formed by the Gulf of Mexico.
Illinois is a state in the midwestern region of the United States, achieving statehood in 1818.
Indiana is a U.S. state located in the midwestern and Great Lakes regions of North America.
The entire outbreak caused more than $600 million in damage in the United States alone, and extensively damaged approximately 900 sq mi along a total combined path length of 2,600 mi.
At one point, as many as 15 separate tornadoes were ongoing at the same time.
The 1974 Super Outbreak was the first tornado outbreak in recorded history to produce more than 100 tornadoes in under a 24 hour period, a feat that was not repeated globally until the 1981 United Kingdom tornado outbreak and in the United States until the 2011 Super Outbreak.