1974 Super Outbreak

1974 Super Outbreak
Paths of the 148 tornadoes
generated in United States during the 1974 Super Outbreak. One tornado was deconfirmed and determined to be a microburst.
Meteorological history
DurationApril 3–4, 1974
Tornado outbreak
Tornadoes148 confirmed
Maximum ratingF5 tornado
Overall effects
Fatalities335 fatalities[1]
Damage$600 million (1974 USD)
$3.97 billion (2024 USD)
Areas affectedMidwestern and Southern United States, Ontario, Canada
Part of the tornado outbreaks of 1974

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 violent (F4 or F5 rated) tornadoes confirmed. From April 3–4, 1974, there were 148 tornadoes confirmed in 13 U.S. states and the Canadian province of Ontario.[nb 1] In the United States, tornadoes struck Illinois, Indiana, Michigan, Ohio, Kentucky, Tennessee, Alabama, Mississippi, Georgia, North Carolina, Virginia, West Virginia, and New York. The outbreak caused roughly $600 million USD (equivalent to $3.71 billion in 2023) in damage.[3] The outbreak extensively damaged approximately 900 sq mi (2,331 km2) along a total combined path length of 2,600 mi (4,184 km).[2][4] At one point, as many as 15 separate tornadoes were occurring simultaneously.[2][5]

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[6] and in the United States until the 2011 Super Outbreak. In 2023, tornado expert Thomas P. Grazulis created the outbreak intensity score (OIS) as a way to rank various tornado outbreaks. The 1974 Super Outbreak received an OIS of 578, making it the most intense tornado outbreak in recorded history.[7]

  1. ^ Corfidi. "Revisiting the 3–4 April 1974 Super Outbreak of Tornadoes" (PDF). spc.noaa.gov. Archived from the original on April 3, 2024. Retrieved April 3, 2024.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  2. ^ a b c Fujita, T. Theodore; Abbey, Robert F. Jr. (1983) [1981]. "Chapter 3: Tornadoes: The Tornado Outbreak of 3–4 April 1974". In Kessler, Edwin (ed.). The Thunderstorm in Human Affairs (2nd ed.). Norman, Oklahoma: University of Oklahoma Press. pp. 37–66.
  3. ^ "The Super Outbreak of April 3-4, 1974". National Weather Service Wilmington, Ohio.
  4. ^ Analysis and reconstruction of the 1974 tornado Super Outbreak (PDF) (Report). Risk Management Solutions. April 2, 2004. p. 9. Archived from the original (PDF) on October 23, 2013. Retrieved April 6, 2014. In total, 148 tornadoes spanned 13 states producing about 900 square miles (2,300 square kilometres) of tornado damage in less than 18 hours. ... Most of the tornadoes were produced by individual thunderstorm cells within these lines. The individual tornadoes moved northeastward at 40–60 mph (64–97 km/h), while the larger scale squall-line systems advanced toward the southeast. ... Many of these tornadoes were part of 'families' or a sequence of tornadoes spawned in succession by a single thunderstorm cell. Dr. Ted Fujita identified 30 such tornado families that accounted for 74% of the Outbreak's tornadoes and resulted in 98% of the 315 deaths. The longest-lasting tornado family existed for nearly five hours, while the average life was approximately two hours.
  5. ^ Forbes, G. S. (1975). "Relationship between tornadoes and hook echoes on April 3, 1974". Preprints. Ninth Conf. on Severe Local Storms. Boston: American Meteorological Society. pp. 280–85.
  6. ^ Rowe, M. W.; Meaden, G. T. (August 1, 1985). "Britain's Greatest Tornado Outbreak". Weather. 40 (8): 230–235. Bibcode:1985Wthr...40..230R. doi:10.1002/j.1477-8696.1985.tb06883.x.
  7. ^ Grazulis, Thomas P. (2023). Significant Tornadoes 1974–2022. St. Johnsbury, Vermont: The Tornado Project. p. 637. ISBN 978-1-879362-01-7.


Cite error: There are <ref group=nb> tags on this page, but the references will not show without a {{reflist|group=nb}} template (see the help page).