Jump to content

EF5 drought

Add links
From Wikipedia, the free encyclopedia
EF5 vs. "Candidate EF5" tornadoes in the United States, 2010-2025[note 1]
  EF5 tornadoes in the United States
  "Candidate EF5" tornadoes outlined in the 2025 study

Since 2013, the United States has experienced a record lack of tornadoes that have been rated EF5 on the Enhanced Fujita Scale by the National Weather Service.[1] This period, dubbed the EF5 drought or EF5 gap by some media outlets,[2] is the longest drought of EF5 tornadoes in recorded history.[3] The drought began following the 2013 Moore EF5 tornado; no EF5 tornadoes have been recorded worldwide since then.[4] Several tornadoes since May 2013 have subsequently been rated as high-end EF4; many of these ratings have attracted significant controversy, notably following the 2014 Mayflower–Vilonia, Arkansas EF4 tornado.[5] The drought has led to questioning whether the Enhanced Fujita scale is an effective way to rate tornadoes,[6] and a 2025 study found that the drought has had a 0.3% chance of running for as long as it has.[6] As of February 2025, the drought of officially-rated EF5 tornadoes is ongoing, spanning over 4,000 days.[2]

Background

[edit]
Further information: Enhanced Fujita scale

The Enhanced Fujita (EF) scale is a damage scale that rates tornado intensity based on the severity of the damage they cause. It is used in some countries, including the United States and France.[7] The EF scale is also unofficially used in other countries, including China and Brazil.[8][9] The rating of a tornado is determined by conducting a tornado damage survey.[10]

History

[edit]

The drought began on May 20, 2013, following the dissipation of the 2013 Moore, Oklahoma EF5 tornado.[11][12] Several tornadoes since the Moore EF5 have reached the 200 miles per hour (320 km/h) wind speeds needed for a tornado to be classified as an EF5, including the 2013 El Reno EF3 tornado and 2015 Rochelle–Fairdale EF4 tornado, with wind speeds measured in excess of 295 miles per hour (475 km/h) and 199 miles per hour (320 km/h), respectively.[13][14]

The May 31, 2013 El Reno tornado, the widest and one of the most powerful ever recorded, was initially rated as an EF5, although this rating was downgraded to an EF3 later in the year.[15] The downgraded rating of the tornado called into question the reliability of the Enhanced Fujita scale, and whether damage scales should be used at all to rate tornadoes.[16]

High-end EF4 damage to a block of homes in the Vilonia, Arkansas area. Many argued that the damage was consistent with an EF5 tornado.

The drought first attracted major attention when the 2014 Mayflower–Vilonia tornado received a final rating of EF4; the rating of the tornado was a source of significant controversy. The National Weather Service office in Little Rock noted that if this tornado occurred prior to the change to the Enhanced Fujita Scale in 2007, it likely would have been rated as an F5 due to numerous homes being swept clean from their foundations. However, it was revealed that almost every home in Vilonia lacked anchor bolts and were anchored with cut nails instead.[17] The new scale accounts for homes that use cut nails instead of anchor bolts, which do not effectively provide resistance against violent tornadoes.[5]

The final decision on an EF4 rating was based on this as well. However, meteorologist and civil engineer Timothy P. Marshall noted in his survey of the damage that the rating assigned was "lower bound", and despite the presence of construction flaws, this doesn't rule out "the possibility that EF5 winds could have occurred."[18][5] Further inspection from surveyors revealed that one home that was swept away along E Wicker St. was indeed properly bolted to its foundation. However, an inspection of the context surrounding the house revealed that small trees in a ditch near the home were still standing, and that the residence had possibly been pummeled by heavy debris from downtown Vilonia, exacerbating the level of destruction.[5]

On May 20, 2021, the drought became the longest in history, surpassing the previous drought that spanned from May 1999 to May 2007.[19]

In 2022, Timothy P .Marshall; Zachary B. Wienhoff, both with the Haag Engineering Company; Christine L. Wielgos, a meteorologist at the National Weather Service of Paducah; and Brian E. Smith, a meteorologist at the National Weather Service of Omaha, published a damage survey of portions of the 2021 Western Kentucky EF4 tornado's track, particularly through Mayfield, Kentucky and Dawson Springs, Kentucky. The report noted that "the tornado damage rating might have been higher had more wind resistant structures been encountered. Also, the fast forward speed of the tornado had little 'dwell' time of strong winds over a building and thus, the damage likely would have been more severe if the tornado were slower."[20] Marshall later stated in 2023 that the Western Kentucky tornado was "the closest to EF5 that I can remember" since the Moore EF5 of 2013.[21] Marshall also stated some of the buildings struck by the strongest winds "were horribly constructed and could not resist 100 or even 150 mph wind let alone 200 mph", meaning it was "impossible to know if EF5 winds affected them".[21]

Damage to downtown Mayfield, Kentucky following the 2021 EF4 tornado

In March 2024, Logan Poole, a meteorologist and damage surveyor with the National Weather Service in Jackson, Mississippi gave an interview regarding the tornado and why the 2023 Rolling Fork–Silver City tornado was rated an EF4 rather than EF5.[22] In the interview, Poole stated:

"So, what gave it the 195 mark? And, the best answer to that is what didn't give it the 200 mark...The Green Apple Florist, essentially a single family home that was modified to built to be a floral shop and it is slabbed to the ground and swept clean. Why not F5? Why not EF5? And two things really stuck out to us from the consensus on why not EF5. One was this building, even though it was extremely, extremely destroyed, I mean on its own, taken out of context, I think most people would agree this would be representative of an EF5 tornado; the damage to that building...If there had even been two of these side-by-side that had suffered the same fate, then maybe we could have had more confidence on that, but we didn't...But it was, to that point that we were very very close and this is probably about as close as you'll get across that threshold, without making it...A question we get a whole lot is like how can you be so sure that it was a five miles per hour from F5, but not quite there? And the answer to that is we aren't. What the EF-scale is, is a damage scale...Is it possible that it had winds that were stronger? Certainly."

— Logan Poole, National Weather Service in Jackson, Mississippi[22]

On April 30, 2024, a large tornado moved through rural farmland near Hollister, Oklahoma. Despite the tornado having the strongest rotational velocity ever observed, it was given a rating of EF1.[23][24] Following the Hollister tornado, meteorologist Eric Graves stated that the "EF scale needed to be amended".[24] The EF4 rating of the May 2024 Greenfield, Iowa tornado that took place less than a month later also attracted significant controversy. A Doppler on Wheels truck measured wind speeds in excess of 300 miles per hour (480 km/h),[25][26] which made the tornado one of the strongest ever recorded and would classify it as an EF5. However, damage survey teams only found damage consistent with a high-end EF4 tornado and as a result it was rated as such.[27][25]

May 2024 study

[edit]

In May 2024, researchers with the University of Western Ontario's Northern Tornado Project and engineering department conducted a case study on the 2018 Alonsa EF4 tornado, the 2020 Scarth EF3 tornado, and the 2023 Didsbury EF4 tornado. In their case study, the researchers assessed extreme damage caused by the tornado which is ineligible for ratings on the Canadian Enhanced Fujita scale or the American Enhanced Fujita scale. In their analysis, it was determined all three tornadoes caused damage well-beyond their assigned ratings, with all three tornadoes having EF5-intensity winds; Alonsa with 127 metres per second (280 mph; 460 km/h), Scarth with 110–119 metres per second (250–270 mph; 400–430 km/h), and Didsbury with 119 metres per second (270 mph; 430 km/h). At the end of the analysis, the researchers stated, "the lofting wind speeds given by this model are much higher than the rating based on the ground survey EF-scale assessment. This may be due to the current tendency to bias strong EF5 tornadoes lower than reality, or limitations in conventional EF-scale assessments".[28]

January 2025 study

[edit]

A 2025 study produced by the National Severe Storms Laboratory and the University of Oklahoma's School of Meteorology found that the probability of no EF5-rated tornadoes happening within an eleven year span would be approximately 0.3%, contrary to the 55.6% of no EF5 tornado happening per year up to 2023.[6] The study also questioned the reliability of the scale as a whole, asking "should tornado ratings be more reflective of total impact, and not solely tied to wind speed estimates?" while citing the four EF5 tornadoes during the 2011 Super Outbreak as a reason for inaccurate percentages.[6]

EF3–EF4 tornadoes outlined in the 2025 study[6]
Tornado Max. estimated windspeeds
2011 Cullman–Arab, AL tornado 190 miles per hour (310 km/h)
2011 Pisgah–Higdon, AL tornado 190 miles per hour (310 km/h)
2011 Tuscaloosa–Birmingham, AL tornado 190 miles per hour (310 km/h)
2011 New Harmony, TN tornado 190 miles per hour (310 km/h)
2011 Ringgold, GA/Apison, TN tornado 190 miles per hour (310 km/h)
2011 Chickasha–Blanchard, OK tornado 200 miles per hour (320 km/h)
2011 Goldsby, OK tornado 200 miles per hour (320 km/h)
2013 Shawnee, OK tornado 190 miles per hour (310 km/h)
2013 Washington, IL tornado 190 miles per hour (310 km/h)
2014 Mayflower–Vilonia, AR tornado 190 miles per hour (310 km/h)
2014 Pilger, NE tornado 191 miles per hour (307 km/h)
2015 Rochelle–Fairdale, IL tornado 200 miles per hour (320 km/h)
2020 Bassfield–Soso, MS tornado 190 miles per hour (310 km/h)
2021 Western KY tornado 190 miles per hour (310 km/h)
2023 Rolling Fork–Silver City, MS tornado 195 miles per hour (314 km/h)

Cause

[edit]

Although there is no official reasoning as to why to drought is ongoing, there are several generally accepted reasons, including:

  • A lack of tornadoes that have reached EF5-level wind speeds[29]
  • A lack of well-constructed buildings in areas where tornadoes are most frequent, which are needed for tornadoes to receive an EF5 rating[11][30]
  • Inconsistencies with the Enhanced Fujita Scale and lack of proper rating system[31]
  • Overall flaws with the Enhanced Fujita Scale[32]
  • Difficulty in finding EF5 Damage Indicators (DIs) due to level of destruction[33]

See also

[edit]

Notes and citations

[edit]

Notes

[edit]
  1. ^ The spike of EF5 tornadoes during the year 2011 includes the 2011 Smithville tornado, 2011 Rainsville tornado, 2011 Hackleburg-Phil Campbell tornado and 2011 Philadelphia tornado during the 2011 Super Outbreak, and the 2011 Joplin tornado and 2011 El Reno-Piedmont tornado during the Tornado outbreak sequence of May 21–26, 2011.

Citations

[edit]
  1. ^ "How rare is an EF-5 tornado?". WBTW. April 27, 2024. Retrieved February 3, 2025.
  2. ^ a b Livingston, Ian (May 22, 2023). "There's a record drought in the scariest tornadoes. Still be scared". The Washington Post. Retrieved February 2, 2025.
  3. ^ "The Last EF5 Tornado Struck Over 8 Years Ago And That's the Longest Streak Of Its Kind". The Weather Channel. December 11, 2021. Retrieved February 2, 2025.
  4. ^ Caulfield, David (May 26, 2021). "EF5 tornado drought continues". WBND-LD. Retrieved February 2, 2025.
  5. ^ a b c d Brantley, Max (May 5, 2014). "Meteorologist defends EF4 rating on Vilonia tornado". Arkansas Times. Retrieved March 4, 2015.
  6. ^ a b c d e Lyza, Anthony W.; Brooks, Harold E.; Krocak, Makenzie J. (January 23, 2025). "Where Have the EF5s Gone? A Closer Look at the "Drought" of the Most Violent Tornadoes in the United States". American Meteorological Society (aop): 11. doi:10.1175/BAMS-D-24-0066.1. ISSN 0003-0007. Retrieved February 2, 2025.
  7. ^ "Intensité des tornades : l'Échelle améliorée de Fujita - Pédagogie - Comprendre les orages - Keraunos - Observatoire français des tornades et orages violents". Keraunos. Retrieved February 2, 2025.
  8. ^ Chen, Jiayi; Cai, Xuhui; Wang, Hongyu; Kang, Ling; Zhang, Hongshen; Song, Yu; Zhu, Hao; Zheng, Wei; Li, Fengju (2018). "Tornado climatology of China". International Journal of Climatology. 38 (5): 2478–2489. Bibcode:2018IJCli..38.2478C. doi:10.1002/joc.5369 – via Royal Meteorological Society.
  9. ^ brunozribeiro (2023-06-09). "PRETS completes 5 years of data!". Reporting Platform and Voluntary Network of Severe Storm Observers (PREVOTS) (in Portuguese, English, and Spanish). Brazil. Retrieved 2024-12-20.
  10. ^ "The Enhanced Fujita Scale (EF Scale)". National Weather Service. Retrieved 2025-02-03.
  11. ^ a b Ferrell, Jesse (May 20, 2024). "U.S. hasn't seen an EF5 tornado in 11 years, longest gap in history". United Press International. AccuWeather. Retrieved February 2, 2025.
  12. ^ Donegan, Brian (May 20, 2023). "Record EF-5 tornado drought extended as US marks 11 years since last one". FOX Weather. Retrieved February 2, 2025.
  13. ^ Painter, Bryan; Allen, Silas (June 5, 2013). "El Reno tornado is 'super rare' national record-breaker". The Oklahoman. Retrieved February 2, 2025.
  14. ^ "April 9, 2015, Tornadoes". National Weather Service Chicago, Illinois. Retrieved February 2, 2025.
  15. ^ "Record 2.6-mile wide Oklahoma tornado downgraded to EF3 by weather service". AL. September 3, 2013. Retrieved February 3, 2025.
  16. ^ Finger, Stan (August 6, 2014). "Downgrading Oklahoma tornado could have long-term ramifications". The Wichita Eagle. Retrieved February 3, 2025.
  17. ^ "No EF5 This Time: Anchor Bolts Not Detected in Most Construction". National Weather Service. Retrieved February 2, 2025.
  18. ^ Marshall, Timothy (November 6, 2014). "Damage Survey of the Mayflower-Vilonia, Arkansas Tornado". American Meteorological Society. Retrieved December 11, 2014.
  19. ^ Mays, Mary (May 19, 2021). "New record EF-5 tornado drought likely this week". WKRN-TV. Retrieved February 2, 2025.
  20. ^ Timothy P. Marshall (Haag Engineering Company); Zachary B. Wienhoff (Haag Engineering Company); Brian E. Smith (NOAA/NWS); Christine L. Wielgos (NOAA/NWS) (January 2023). "Damage Survey of the Mayfield, KY Tornado: 10 December 2021". Academia.edu: 1–13. Retrieved 19 January 2023.
  21. ^ a b Livingston, Ian (22 May 2023). "There's a record drought in the scariest tornadoes. Still be scared". The Washington Post. Archived from the original on 5 December 2023. Retrieved 5 December 2023. Marshall was on one of three teams to survey the Mayfield EF4 and it was "the closest to EF5 that I can remember" since the Moore EF5 of 2013, he said. But as the surveying teams could not find EF5 damage consistent with winds of at least 200 mph, the tornado was ultimately ranked just shy of that mark, with 190 mph winds. Some buildings where the storm's most violent winds struck were completely obliterated, but they were so poorly constructed it was impossible to know if EF5 winds affected them. "They were horribly constructed and could not resist 100 or even 150 mph wind let alone 200 mph," Marshall said.
  22. ^ a b Olsen, Max; Poole, Logan (12 March 2024). "Is That a Car Flying Around This EF-4 Tornado? - The Mystery Continues" (Video). YouTube. Max Olson Chasing. Archived from the original on 19 July 2024. Retrieved 19 July 2024.
  23. ^ "Two Monster Oklahoma Tornadoes Are Inspiring EF-Scale Changes". Z94. May 2, 2024. Retrieved February 3, 2025.
  24. ^ a b Patterson, Kaley (2 May 2024). "Did Oklahoma Really See the Most Powerful Tornado Ever?" (News article). Lawton, Oklahoma: KLAW 101. Archived from the original on 17 May 2024. Retrieved 17 May 2024. The gate velocities were over 260 miles per hour, a vortex hole like the eye of a hurricane and the swirl could be seen from 18,000 feet.
  25. ^ a b Satre, Zane (2024-06-26). "300+ mph: Greenfield, Iowa tornado had some of the strongest winds ever recorded, radar data shows". KCCI. Retrieved 2025-02-03.
  26. ^ Reyna-Rodriguez, Victoria. "Was the Greenfield tornado the strongest tornado ever? What mobile wind speed data shows". The Des Moines Register. Retrieved 2025-02-03.
  27. ^ "Why wasn't the Greenfield tornado rated an EF-5?". who13.com. 2024-07-26. Retrieved 2025-02-03.
  28. ^ Miller, Connell S.; Kopp, Gregory A.; Sills, David M.L.; Butt, Daniel G. (20 May 2024). "Estimating wind speeds in tornadoes using debris trajectories of large compact objects". Monthly Weather Review. -1 (aop). American Meteorological Society: 1859–1881. Bibcode:2024MWRv..152.1859M. doi:10.1175/MWR-D-23-0251.1. Retrieved 29 May 2024.
  29. ^ Henson, Bob (May 25, 2021). "It's been a record-long time since the last EF5 tornado. What does that mean?". Yale Climate Connections. Retrieved February 2, 2025.
  30. ^ "Greenfield tornado upgraded to EF-4: EF-5 drougth continues". Weather & Radar. 2024-05-24. Retrieved 2025-02-03.
  31. ^ Stuzke, Andrew (March 29, 2023). "The 10-year EF-5 tornado drought; Why fewer violent tornadoes are being recorded". WQAD-TV. Retrieved February 2, 2025.
  32. ^ Siffert, Andrew (May 18, 2021). "U.S. EF5 Tornado Drought And Update on U.S. Severe Weather Season". BMS Group. Retrieved February 2, 2025.
  33. ^ "The frightening reason violent EF-5 tornadoes are so rare". The Weather Network. 2024-04-28. Retrieved 2025-02-03.
Retrieved from "https://ergngevd.top/w/index.php?title=EF5_drought&oldid=1273728519"