EF5 drought

{{Further|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.{{cite web |title=Intensité des tornades : l'Échelle améliorée de Fujita - Pédagogie - Comprendre les orages - Keraunos - Observatoire français des tornades et orages violents |url=https://www.keraunos.org/recherche/comprendre-les-orages-pedagogie-vulgarisation/tornades-trombes-tubas/intensite-tornade-echelle-fujita-amelioree-ef-f-scale.html |access-date=February 2, 2025 |website=Keraunos}} The EF scale is also unofficially used in other countries, including China and Brazil.{{cite journal |last1=Chen |first1=Jiayi |last2=Cai |first2=Xuhui |last3=Wang |first3=Hongyu |last4=Kang |first4=Ling |last5=Zhang |first5=Hongshen |last6=Song |first6=Yu |last7=Zhu |first7=Hao |last8=Zheng |first8=Wei |last9=Li |first9=Fengju |date=2018 |title=Tornado climatology of China |url=https://rmets.onlinelibrary.wiley.com/doi/10.1002/joc.5369 |journal=International Journal of Climatology |volume=38 |issue=5 |pages=2478–2489 |bibcode=2018IJCli..38.2478C |doi=10.1002/joc.5369 |via=Royal Meteorological Society}}{{Cite web |last=brunozribeiro |date=2023-06-09 |title=PRETS completes 5 years of data! |url=http://prevots.org/2023/06/prets-completa-5-anos-de-dados/#:~:text=Em%201%20jun%202023,%20a%20plataforma%20de%20registros,severo%20no%20Brasil%20s%C3%A3o%20catalogados%20a%20cada%20ano. |access-date=2024-12-20 |website=Reporting Platform and Voluntary Network of Severe Storm Observers (PREVOTS) |language=pt, en, es |publication-place=Brazil}} The rating of a tornado is determined by conducting a tornado damage survey.{{Cite web |title=The Enhanced Fujita Scale (EF Scale) |url=https://www.weather.gov/oun/efscale?os=av/&ref=app |access-date=2025-02-03 |website=National Weather Service |language=EN-US}}

{{see also|Disagreements on the intensity of tornadoes}}

The drought began on May 20, 2013, following the dissipation of the 2013 Moore, Oklahoma EF5 tornado.{{Cite web |last=Ferrell |first=Jesse |date=May 20, 2024 |title=U.S. hasn't seen an EF5 tornado in 11 years, longest gap in history |url=https://www.upi.com/Science_News/2024/05/20/EF5-tornado-11-year-gap/4221716215687/ |access-date=February 2, 2025 |website=United Press International |place=AccuWeather |language=en}}{{Cite web |last=Donegan |first=Brian |date=May 20, 2023 |title=Record EF-5 tornado drought extended as US marks 11 years since last one |url=https://www.foxweather.com/extreme-weather/last-ef5-tornado-united-states-record-longest-span |access-date=February 2, 2025 |website=FOX Weather |language=en-US}} Several tornadoes since the Moore EF5 have reached the {{Convert|200|mph|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 {{Convert|295|mph|km/h}} and {{Convert|199|mph|km/h}}, respectively.{{Cite web |last1=Painter |first1=Bryan |last2=Allen |first2=Silas |date=June 5, 2013 |title=El Reno tornado is 'super rare' national record-breaker |url=https://www.oklahoman.com/story/news/columns/2013/06/05/el-reno-tornado-is-super-rare-national-record-breaker/60928429007/ |access-date=February 2, 2025 |website=The Oklahoman |language=en-US}}{{Cite web |title=April 9, 2015, Tornadoes |url=https://www.weather.gov/lot/2015_04_09_tornadoes |access-date=February 2, 2025 |website=National Weather Service Chicago, Illinois |language=EN-US}}

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.{{Cite web |date=September 3, 2013 |title=Record 2.6-mile wide Oklahoma tornado downgraded to EF3 by weather service |url=https://www.al.com/breaking/2013/09/record_26-mile_wide_oklahoma_t.html |access-date=February 3, 2025 |website=AL |language=en}} 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.{{Cite web |last=Finger |first=Stan |date=August 6, 2014 |title=Downgrading Oklahoma tornado could have long-term ramifications |url=https://www.kansas.com/news/article1123440.html |access-date=February 3, 2025 |website=The Wichita Eagle}}File:April 27, 2014 Vilonia tornado aerial damage.jpg 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.{{Cite web |title=No EF5 This Time: Anchor Bolts Not Detected in Most Construction |url=https://www.weather.gov/lzk/anchor0514.htm |access-date=February 2, 2025 |website=National Weather Service |language=EN-US}} The new scale accounts for homes that use cut nails instead of anchor bolts, which do not effectively provide resistance against violent tornadoes.{{cite web |last1=Brantley |first1=Max |date=May 5, 2014 |title=Meteorologist defends EF4 rating on Vilonia tornado |url=http://www.arktimes.com/ArkansasBlog/archives/2014/05/05/meteorologist-defends-ef4-rating-on-vilonia-tornado |access-date=March 4, 2015 |website=Arkansas Times}}

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."{{cite journal |last1=Marshall |first1=Timothy |author-link=Timothy P. Marshall |date=November 6, 2014 |title=Damage Survey of the Mayflower-Vilonia, Arkansas Tornado |url=https://ams.confex.com/ams/27SLS/webprogram/Paper254346.html |journal=American Meteorological Society |access-date=December 11, 2014}} 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.

On May 20, 2021, the drought became the longest in history, surpassing the previous drought that spanned from May 1999 to May 2007.{{Cite web |last=Mays |first=Mary |date=May 19, 2021 |title=New record EF-5 tornado drought likely this week |url=https://www.wkrn.com/weather-headlines/weather-stories/new-record-ef-5-tornado-drought-likely-this-week/ |access-date=February 2, 2025 |website=WKRN-TV |language=en-US}}

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."{{cite journal |author1=Timothy P. Marshall (Haag Engineering Company) |author2=Zachary B. Wienhoff (Haag Engineering Company) |author3=Brian E. Smith (NOAA/NWS) |author4=Christine L. Wielgos (NOAA/NWS) |date=January 2023 |title=Damage Survey of the Mayfield, KY Tornado: 10 December 2021 |url=https://www.academia.edu/90132303 |journal=Academia.edu |pages=1–13 |access-date=19 January 2023}} 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.{{cite news |last1=Livingston |first1=Ian |date=22 May 2023 |title=There's a record drought in the scariest tornadoes. Still be scared. |url=https://www.washingtonpost.com/weather/2023/05/22/tornado-drought-record-moore-ef5/ |url-status=live |archive-url=https://web.archive.org/web/20231205040739/https://www.washingtonpost.com/weather/2023/05/22/tornado-drought-record-moore-ef5/ |archive-date=5 December 2023 |access-date=5 December 2023 |newspaper=The Washington Post |language=English |quote=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.}} 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".File:Mayfield KY State Farm CRU -23.jpg 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.{{cite web |last1=Olsen |first1=Max |last2=Poole |first2=Logan |date=12 March 2024 |title=Is That a Car Flying Around This EF-4 Tornado? - The Mystery Continues |url=https://www.youtube.com/watch?v=MUaYOCI-0K4 |url-status=live |archive-url=https://web.archive.org/web/20240719171231/https://www.youtube.com/watch?v=MUaYOCI-0K4 |archive-date=19 July 2024 |access-date=19 July 2024 |website=YouTube |publisher=Max Olson Chasing |format=Video}} In the interview, Poole stated:

{{Blockquote|text="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 {{as written|bui|lt}} to be a floral shop and it is slabbed to the ground and swept clean. {{Omission}} 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, {{Omission}} 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 {{Omission}} What the EF-scale is, is a damage scale...Is it possible that it had winds that were stronger? Certainly."|author=Logan Poole, National Weather Service in Jackson, Mississippi}}On April 30, 2024, a large tornado moved through rural farmland near Hollister, Oklahoma. Despite the tornado having an exceptionally strong tornado vortex signature on radar, it was given a rating of EF1.{{Cite web |date=May 2, 2024 |title=Two Monster Oklahoma Tornadoes Are Inspiring EF-Scale Changes |url=https://z94.com/oklahoma-tornadoes-ef-scale-changes/ |access-date=February 3, 2025 |website=Z94 |language=en}}{{cite web |last1=Patterson |first1=Kaley |date=2 May 2024 |title=Did Oklahoma Really See the Most Powerful Tornado Ever? |url=https://klaw.com/oklahoma-most-powerful-tornado-ever/ |url-status=live |archive-url=https://web.archive.org/web/20240517170549/https://klaw.com/oklahoma-most-powerful-tornado-ever/ |archive-date=17 May 2024 |access-date=17 May 2024 |publisher=KLAW 101 |language=en |format=News article |quote=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. |location=Lawton, Oklahoma}} Following the Hollister tornado, meteorologist Eric Graves stated that the "EF scale needed to be amended". 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 determined that wind speeds in excess of {{Convert|300|mph|km/h}} could be observed at ground level inside the tornado,{{Cite web |last=Satre |first=Zane |date=2024-06-26 |title=300+ mph: Greenfield, Iowa tornado had some of the strongest winds ever recorded, radar data shows |url=https://www.kcci.com/article/may-21-2024-greenfield-iowa-tornado-had-some-of-the-strongest-winds-ever-recorded/61423120 |access-date=2025-02-03 |website=KCCI |language=en}}{{Cite web |last=Reyna-Rodriguez |first=Victoria |title=Was the Greenfield tornado the strongest tornado ever? What mobile wind speed data shows. |url=https://www.desmoinesregister.com/story/weather/2024/06/27/greenfield-iowa-tornado-strongest-highest-wind-speeds-doppler-on-wheels-university-of-illinois/74231908007/ |access-date=2025-02-03 |website=The Des Moines Register |language=en-US}} 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.{{Cite web |date=2024-07-26 |title=Why wasn't the Greenfield tornado rated an EF-5? |url=https://who13.com/news/iowa-news/why-wasnt-the-greenfield-tornado-rated-an-ef-5/ |access-date=2025-02-03 |website=who13.com |language=en-US}} In a presentation discussing the findings during the Greenfield event by Joshua Wurman and Karen Kosiba, the two researchers leading the team that observed the tornado, the disconnect between wind speed and ground damage was discussed, with one suggestion stating that aerial wind speeds could be disrupted by housing and other structures at ground level that could have prevented them from producing damage, in addition to the tornado's fast forward speed of {{convert|45|mph|km/h}} that caused the tornado to spend less than one minute in Greenfield.{{cite AV media |title= Tornado at the Ground: How DOW data on the Greenfield, IA EF4+ Could Advance Research - 23 July 2024 |publisher=American Meteorological Society |url=https://www.youtube.com/watch?v=aZDYC1ukWi8 |first1=Joshua |last1=Wurman |first2=Karen |last2=Kosiba |format=Presentation via YouTube |date=23 July 2024 |access-date=9 February 2025 |time=21:49 }}

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 {{convert|127|m/s|mph km/h}}, Scarth with {{convert|110-119|m/s|mph km/h}}, and Didsbury with {{convert|119|m/s|mph 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".{{cite journal |last1=Miller |first1=Connell S. |last2=Kopp |first2=Gregory A. |last3=Sills |first3=David M.L. |last4=Butt |first4=Daniel G. |date=20 May 2024 |title=Estimating wind speeds in tornadoes using debris trajectories of large compact objects |url=https://journals.ametsoc.org/view/journals/mwre/aop/MWR-D-23-0251.1/MWR-D-23-0251.1.xml |journal=Monthly Weather Review |publisher=American Meteorological Society |volume=-1 |issue=aop |pages=1859–1881 |bibcode=2024MWRv..152.1859M |doi=10.1175/MWR-D-23-0251.1 |access-date=29 May 2024}}

A 2025 case study, produced by Anthony Lyza with the National Severe Storms Laboratory and other researchers with the University of Oklahoma's School of Meteorology,{{Cite web |title=New Study Reveals The Lack Of EF5 Tornadoes |url=https://weather.com/storms/tornado/video/11-year-ef5-tornado-drought-explained |access-date=2025-02-26 |website=The Weather Channel |language=en-US}} published with the American Meteorological Society, 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.{{Cite journal |last1=Lyza |first1=Anthony W. |last2=Brooks |first2=Harold E. |last3=Krocak |first3=Makenzie J. |date=January 23, 2025 |title=Where Have the EF5s Gone? A Closer Look at the "Drought" of the Most Violent Tornadoes in the United States |url=https://journals.ametsoc.org/view/journals/bams/aop/BAMS-D-24-0066.1/BAMS-D-24-0066.1.xml?tab_body=pdf |journal=American Meteorological Society |language=EN |issue=aop |page=11 |doi=10.1175/BAMS-D-24-0066.1 |issn=0003-0007 |access-date=February 2, 2025 |doi-access=free}} 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. The case study was added into the National Oceanic and Atmospheric Administration’s Library shortly after its publication.{{cite web |title=NOAA Central Library Journals (QC851 .A6) |url=https://discover.library.noaa.gov/permalink/01NOAA_INST/n34dum/cdi_crossref_primary_10_1175_BAMS_D_24_0066_1 |publisher=National Oceanic and Atmospheric Administration |access-date=4 February 2025 |date=2025}}

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

• A lack of tornadoes that have reached EF5-level wind speeds{{Cite web |last=Henson |first=Bob |date=May 25, 2021 |title=It's been a record-long time since the last EF5 tornado. What does that mean? |url=https://yaleclimateconnections.org/2021/05/its-been-a-record-long-time-since-the-last-ef5-tornado-what-does-that-mean/ |access-date=February 2, 2025 |website=Yale Climate Connections |language=en-US}}
• A lack of well-constructed buildings in areas where tornadoes are most frequent, which are needed for tornadoes to receive an EF5 rating{{Cite web |date=2024-05-24 |title=Greenfield tornado upgraded to EF-4: EF-5 drougth continues |url=https://www.weatherandradar.com/weather-news/greenfield-tornado-upgraded-to-ef-4-ef-5-drougth-continues--7cf9c185-e995-4ce1-bf69-c60bd79ac969 |access-date=2025-02-03 |website=Weather & Radar |language=en}}
• Inconsistencies with the Enhanced Fujita Scale and lack of proper rating system{{Cite web |last=Stuzke |first=Andrew |date=March 29, 2023 |title=The 10-year EF-5 tornado drought; Why fewer violent tornadoes are being recorded |url=https://www.wqad.com/article/weather/ask-andrew/fewer-ef5-tornadoes-enhanced-fujita-scale/526-f70eb673-d294-4a36-8bc6-1766c7598af6 |access-date=February 2, 2025 |website=WQAD-TV |language=en-US}}
• Overall flaws with the rating procedures used when applying the Enhanced Fujita Scale{{Cite web |last=Siffert |first=Andrew |date=May 18, 2021 |title=U.S. EF5 Tornado Drought And Update on U.S. Severe Weather Season |url=https://www.bmsgroup.com/news/u-s-ef5-tornado-drought-and-update-u-s-severe-weather-season |access-date=February 2, 2025 |website=BMS Group |language=en-GB}}
• Difficulty in finding EF5 Damage Indicators (DIs) due to level of destruction{{Cite web |date=2024-04-28 |title=The frightening reason violent EF-5 tornadoes are so rare |url=https://www.theweathernetwork.com/en/news/science/explainers/the-frightening-reason-violent-ef-5-tornadoes-are-so-rare |access-date=2025-02-03 |website=The Weather Network |language=en-ca}}
• Subjectivity in rating of DIs{{Cite web |title=The Reason Behind Our 11 Year EF5 Tornado Drought |url=https://weather.com/storms/tornado/news/2025-02-25-the-reason-behind-us-ef5-tornado-drought |access-date=2025-02-26 |website=The Weather Channel |language=en-US}}{{Cite web |last=Wulfeck |first=Andrew |date=2025-02-22 |title=Absence of EF-5 tornadoes may be because of damage assessments, not changes in weather patterns |url=https://www.foxweather.com/weather-news/enhanced-tornado-scale |access-date=2025-02-26 |website=FOX Weather |language=en-US}}

• Disagreements on the intensity of tornadoes
• Tornado records

{{Reflist|group=note}}

{{reflist}}{{EF scale}}

Category:Tornadoes in the United States

Category:Controversies in the United States