Global InformationTornadoes of 1973 information
 Tracks of all US tornadoes in 1973. | |
| Timespan | January 10–December 31, 1973 |
|---|---|
| Maximum rated tornado | F5 tornado
|
| Tornadoes in U.S. | 1102 |
| Damage (U.S.) | Unknown |
| Fatalities (U.S.) | 89 |
| Fatalities (worldwide) | >833 |
This page documents notable tornadoes and tornado outbreaks worldwide in 1973, but mostly features events in the United States. According to tornado researcher Thomas P. Grazulis, 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.[1] Most countries only recorded tornadoes that produced severe damage or loss of life.[2] Consequently, available documentation in 1973 mainly covered the United States. On average, most recorded tornadoes, including the vast majority of significant—F2[nb 1] or stronger—tornadoes, form in the U.S., although as many as 500 may take place internationally.[1] Some locations, like Bangladesh, are as prone to violent tornadoes as the U.S., meaning F4 or greater events on the Fujita scale.[7]
Historically, the number of tornadoes globally[1] 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.[8] 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.[9] Owing to increases in storm spotters, the number of tornadoes in the U.S. reached new heights in the early 1970s.[8] 1973 was the first year in which more than 1,000 tornadoes were verified in the United States.[10] The long-term annual mean for the U.S. is roughly 1,300 tornadoes each year,[2] though Grazulis estimates that the real total may be close to 1,800.[11] Despite having the highest annual total in the nation to date, 1973 failed to establish records in terms of significant or killer tornadoes—several earlier years had already done so.[12]
Notable scientific milestones toward understanding the life cycle of tornadoes occurred in Oklahoma on May 24, 1973, when researchers exploited primitive Doppler weather radar, then under development by the National Severe Storms Laboratory (NSSL), to examine a tornado vortex signature, or TVS, for the first time in history.[10][13] The scientists, in one of the earliest successful cases of storm chasing, were able to study the evolution of a violent tornado near Union City, and to generate clear visual photography of its entire life cycle, from birth to decay. The successful deployment of Doppler weather radar to detect tornado formation also pointed the way to the development of a nationwide Doppler radar system, and helped precipitate funding for studies on tornadogenesis.[10][13]
- ^ a b c Grazulis, Thomas P. (2001). The Tornado: Nature's Ultimate Windstorm. Norman: University of Oklahoma Press. pp. 251–254. ISBN 978-0-8061-3538-0.
- ^ a b Edwards, Roger (5 March 2015). "The Online Tornado FAQ (by Roger Edwards, SPC)". Storm Prediction Center: Frequently Asked Questions about Tornadoes. Storm Prediction Center. Retrieved 25 February 2016.
- ^ Grazulis 1993, p. 141
- ^ Edwards, Roger (5 March 2015). "Enhanced F Scale for Tornado Damage". The Online Tornado FAQ (by Roger Edwards, SPC). Storm Prediction Center. Retrieved 25 February 2016.
- ^ "Enhanced Fujita Scale (EF-Scale)". Environment and Climate Change Canada. 6 June 2013. Archived from the original on 3 March 2016. Retrieved 25 February 2016.
- ^ "The International Tornado Intensity Scale". Tornado and Storm Research Organisation. 2016. Archived from the original on 5 March 2016. Retrieved 25 February 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. p. 128. ISBN 1-879362-03-1.
- ^ a b Grazulis 2001, pp. 207–208
- ^ Cook, A. R.; Schaefer, J. T. (August 2008). "The Relation of El Niño–Southern Oscillation (ENSO) to Winter Tornado Outbreaks". Monthly Weather Review. 136 (8): 3135. Bibcode:2008MWRv..136.3121C. doi:10.1175/2007MWR2171.1.
- ^ a b c Grazulis 2001, p. 242
- ^ Grazulis 2001, p. 211
- ^ Grazulis 2001, pp. 209, 229
- ^ a b Grazulis 2001, pp. 35, 63
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