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Hurricane Hilda tornado outbreak

Map plotting the track and intensity of the storm, according to the Saffir–Simpson scale
Type	Tornado outbreak Tropical cyclone
Duration	October 3–4, 1964
Tornadoes confirmed	12
Max. rating	F4 tornado
Duration of tornado outbreak	1 day, 11 hours, 30 minutes
Fatalities	22 fatalities, 175 injuries
Damage	≥ $8.107 million (1964 USD) $79.6 million (2024 USD)
Areas affected	Southeastern United States
Part of the tornadoes and tornado outbreaks of 1964 Most severe tornado damage; see Fujita scale Time from first tornado to last tornado

On October 3–4, 1964, Hurricane Hilda and its remnants generated a tornado outbreak over portions of the Southeastern United States. The outbreak, which yielded at least 12 confirmed tornadoes, killed 22 people and injured 175 others. Most of the casualties occurred as a result of the 1964 Larose tornado that devastated the northern outskirts of Larose, Louisiana, becoming the deadliest hurricane-generated tornado on record since 1900 and one of only two violent tornadoes (F4+) recorded in the southern Gulf Coast region of Louisiana. The tornado was also one of only two F4s known to have been produced by a tropical cyclone, the other having occurred during Hurricane Carla on September 12, 1961.

Background

At 23:00 UTC on October 3, 1964, Hurricane Hilda made landfall at 29°30′N 91°30′W / 29.5°N 91.5°W / 29.5; -91.5, near Calumet, Louisiana, with maximum sustained winds of 105 mph (169 km/h) and an estimated atmospheric pressure of 959 mb (28.3 inHg). Although Hilda extensively damaged portions of Louisiana, most of its severest impacts, including the vast majority of fatalities, were related to hurricane-spawned tornadoes, along with inland flooding.

Outbreak statistics

Confirmed tornadoes

October 3 event

October 4 event

See also

• List of North American tornadoes and tornado outbreaks
• List of tornadoes spawned by tropical cyclones

Notes

1. All losses are in 1964 USD unless otherwise noted.
2. An outbreak is generally defined as a group of at least six tornadoes (the number sometimes varies slightly according to local climatology) with no more than a six-hour gap between individual tornadoes. An outbreak sequence, prior to (after) the start of modern records in 1950, is defined as a period of no more than two (one) consecutive days without at least one significant (F2 or stronger) tornado.
3. The Fujita scale was devised under the aegis of scientist T. Theodore Fujita in the early 1970s. Prior to the advent of the scale in 1971, tornadoes in the United States were officially unrated. While the Fujita scale has been superseded by the Enhanced Fujita scale in the U.S. since February 1, 2007, Canada used the old scale until April 1, 2013; nations elsewhere, like the United Kingdom, apply other classifications such as the TORRO scale.
4. Historically, the number of tornadoes globally and in the United States was and is likely underrepresented: research by Grazulis on annual tornado activity suggests that, as of 2001, only 53% of yearly U.S. tornadoes were officially recorded. Documentation of tornadoes outside the United States was historically less exhaustive, owing to the lack of monitors in many nations and, in some cases, to internal political controls on public information. Most countries only recorded tornadoes that produced severe damage or loss of life. Significant low biases in U.S. tornado counts likely occurred through the early 1990s, when advanced NEXRAD was first installed and the National Weather Service began comprehensively verifying tornado occurrences.
5. ^ All dates are based on the local time zone where the tornado touched down; however, all times are in Coordinated Universal Time and dates are split at midnight CST/CDT for consistency.
6. ^ Prior to 1994, only the average widths of tornado paths were officially listed.

References

1. ^ Storm Data Publication 1964, Events Reported
2. ^ Edwards 2012, p. 2.
3. ^ Hagemeyer, Bartlett C.; Spratt, Scott M. (2002). Written at Melbourne, Florida. Thirty Years After Hurricane Agnes: the Forgotten Florida Tornado Disaster (PDF). 25th Conference on Hurricanes and Tropical Meteorology. San Diego, California: American Meteorological Society. Archived from the original (PDF) on October 16, 2008.
4. Grazulis, Thomas P.; Grazulis, Doris (April 26, 2000). "The United States' Worst Tornadoes". The Tornado Project. St. Johnsbury, Vermont: Environmental Films. Archived from the original on May 14, 2008. Retrieved August 18, 2021.
5. Schneider, Russell S.; Brooks, Harold E.; Schaefer, Joseph T. (2004). Tornado Outbreak Day Sequences: Historic Events and Climatology (1875–2003) (PDF). 22nd Conf. Severe Local Storms. Hyannis, Massachusetts: American Meteorological Society. Retrieved September 17, 2019.
6. Grazulis 1993, p. 141.
7. Grazulis 2001a, p. 131.
8. Edwards, Roger (March 5, 2015). "Enhanced F Scale for Tornado Damage". The Online Tornado FAQ (by Roger Edwards, SPC). Storm Prediction Center. Retrieved February 25, 2016.
9. "Enhanced Fujita Scale (EF-Scale)". Environment and Climate Change Canada. June 6, 2013. Archived from the original on March 3, 2016. Retrieved February 25, 2016.
10. "The International Tornado Intensity Scale". Tornado and Storm Research Organisation. 2016. Archived from the original on March 5, 2016. Retrieved February 25, 2016.
11. Grazulis 2001a, pp. 251–4.
12. Edwards, Roger (March 5, 2015). "The Online Tornado FAQ (by Roger Edwards, SPC)". Storm Prediction Center: Frequently Asked Questions about Tornadoes. Storm Prediction Center. Retrieved February 25, 2016.
13. Cook & Schaefer 2008, p. 3135
14. IBTrACS 2021, 1964273N21280
15. U.S. Weather Bureau (1961). "Page 5". Preliminary report on Hurricane "Hilda". National Hurricane Center (Report). Miami: National Oceanic and Atmospheric Administration. Retrieved December 19, 2024.
16. Roth, David. "Hurricane Hilda - September 28 – October 5, 1964". Tropical Cyclone Point Maxima. Silver Spring, Maryland: United States National Oceanic and Atmospheric Administration's Weather Prediction Center. Retrieved June 10, 2014.
17. ^ USWB 1964, p. 106.
18. ^ USWB 1964, p. 108.
19. Brooks 2004, p. 310.
20. Storm Data Publication 1964, #10030798
21. ^ USWB 1964, p. 107.
22. Storm Data Publication 1964, #10030799
23. Storm Data Publication 1964, #10030801
24. ^ Grazulis 1993, p. 1057.
25. Storm Data Publication 1964, #10030802
26. Storm Data Publication 1964, #10030803
27. Storm Data Publication 1964, #10030804
28. Storm Data Publication 1964, #10048245
29. Storm Data Publication 1964, #10030805
30. Storm Data Publication 1964, #9978107
31. Storm Data Publication 1964, #9978108
32. Storm Data Publication 1964, #10077779
33. Storm Data Publication 1964, #9978109
34. Storm Data Publication 1964, #10077994

Sources

• Brooks, Harold E. (April 2004). "On the Relationship of Tornado Path Length and Width to Intensity". Weather and Forecasting. 19 (2). Boston: American Meteorological Society: 310–19. Bibcode:2004WtFor..19..310B. doi:10.1175/1520-0434(2004)019<0310:OTROTP>2.0.CO;2.
• Cook, A. R.; Schaefer, J. T. (August 2008). Written at Norman, Oklahoma. "The Relation of El Niño–Southern Oscillation (ENSO) to Winter Tornado Outbreaks". Monthly Weather Review. 136 (8). Boston: American Meteorological Society: 3135. Bibcode:2008MWRv..136.3121C. doi:10.1175/2007MWR2171.1.
• Edwards, Roger (2012). "Tropical cyclone tornadoes: A review of knowledge in research and prediction". Electronic Journal of Severe Storms Meteorology. 7 (6): 1–61. doi:10.55599/ejssm.v7i6.42. Archived from the original on March 16, 2016.
• Grazulis, Thomas P. (July 1993). Significant Tornadoes 1680–1991: A Chronology and Analysis of Events. St. Johnsbury, Vermont: The Tornado Project of Environmental Films. ISBN 1-879362-03-1.
• Grazulis, Thomas P. (2001a). The Tornado: Nature's Ultimate Windstorm. Norman: University of Oklahoma Press. ISBN 978-0-8061-3538-0.
• Grazulis, Thomas P. (2001b). F5-F6 Tornadoes. St. Johnsbury, Vermont: The Tornado Project of Environmental Films.
• International Best Track Archive for Climate Stewardship (IBTrACS) (May 2021). IBTrACS browser (hosted by UNC Asheville) (Report). National Centers for Environmental Information – via World Data Center for Meteorology.
• National Weather Service (October 1964). Storm Data Publication (Report). National Centers for Environmental Information – via Storm Events Database.
• U.S. Weather Bureau (October 1964). "Storm Data and Unusual Weather Phenomena". Storm Data. 6 (10). Asheville, North Carolina: National Climatic Data Center.

• F4 tornadoes
• Tornadoes of 1964
• Tornadoes in Louisiana
• 1964 in Louisiana
• Tornado outbreaks spawned by tropical cyclones