Enhanced Fujita scale#Rating classifications

The Enhanced Fujita scale replaced the decommissioned Fujita scale that was introduced in 1971 by Ted Fujita.Fujita, T. Theodore (February 1971) [https://swco-ir.tdl.org/handle/10605/261875 "Proposed characterization of tornadoes and hurricanes by area and intensity"]. SMRP (Satellite and Mesometeorology Research Project) Research Paper 91 (Department of the Geophysical Sciences, University of Chicago, Chicago, Illinois, USA) 42 pages. Operational use began in the United States on February 1, 2007, followed by Canada on April 1, 2013, who uses a modified version known as the CEF-scale.{{Cite web |title=Fujita Tornado Damage Scale |url=http://www.spc.noaa.gov/faq/tornado/f-scale.html |website=www.spc.noaa.gov}}{{Cite web |title=Tornado Scale - The Enhanced Fujita Scale |url=http://www.tornadofacts.net/tornado-scale.php |website=TornadoFacts.net |url-status=live |archive-url=https://web.archive.org/web/20171218075226/http://www.tornadofacts.net/tornado-scale.php |archive-date= Dec 18, 2017 }}{{cite web |date=May 10, 2013 |title=Enhanced Fujita Scale |url=http://www.ec.gc.ca/meteo-weather/default.asp?lang=En&n=41E875DA-1 |publisher=Environment Canada}}{{cite book |last1=Repetto |first1=Maria Pia |last2=Burlando |first2=Massimiliano |title=Thunderstorm Outflows and their Impact on Structures |date=March 2023 |publisher=University of Genoa |isbn=978-88-3618-210-7 |page=31 |url=https://gup.unige.it/sites/gup.unige.it/files/pagine/Thunderstorm_Outflows_and_their_Impact_on_Structures_ebook.pdf |access-date=11 June 2024 |quote=Next, four damage-based wind speed rating methods for tornados are introduced: the Fujita-Scale (F-Scale); the Enhanced Fujita-Scale (EF-Scale); the Canadian Enhanced Fujita-Scale (CEF-Scale); and the Japanese Enhanced Fujita-Scale (JEF-Scale)...The CEF-Scale was proposed in 2013 by Environment Canada, closely following the EF-Scale, while the CEF-Scale uses 31 DIs.}}{{cite web |author1=Pieter Groenemeijer (ESSL) |author2=Lothar Bock (DWD) |author3=Juan de Dios Soriano (AEMet) |author4=Maciej Dutkiewicz (Bydgoszcz University of Science and Technology) |author5=Delia Gutiérrez-Rubio (AEMet) |author6=Alois M. Holzer (ESSL) |author7=Martin Hubrig |author8=Rainer Kaltenberger |author9=Thilo Kühne (ESSL) |author10=Mortimer Müller (Universität für Bodenkultur) |author11=Bas van der Ploeg |author12=Tomáš Púčik (ESSL) |author13=Thomas Schreiner (ESSL) |author14=Miroslav Šinger (SHMI) |author15=Gabriel Strommer (ESSL) |author16=Andi Xhelaj (University of Genova) |title=The International Fujita (IF) Scale |url=https://www.essl.org/cms/wp-content/uploads/IF-scale_v1.0.pdf |publisher=European Severe Storms Laboratory |access-date=30 July 2023 |date=30 July 2023}} It has also been in use in France since 2008, albeit modified slightly by using damage indicators that take into account French construction standards, native vegetation, and the use of metric units.{{cite web |last=KERAUNOS |title=Intensité des tornades : l'échelle de Fujita améliorée |url=https://www.keraunos.org/recherche/comprendre-les-orages-pedagogie-vulgarisation/tornades-trombes-tubas/intensite-tornade-echelle-fujita-amelioree-ef-f-scale.html}} In Brazil, the EF Scale is used by the Reporting Platform and Voluntary Network of Severe Storm Observers (PREVOTS) since June 2018. Similarly, the Japanese implementation of the scale is also modified along similar lines; the Japanese variant is referred to locally in Japan as the JEF or Japanese Enhanced Fujita Scale.{{Cite journal |last1=Suzuki |first1=Shota |last2=Tanaka |first2=Yoshinobu |title=The Japanese Enhanced Fujita Scale: Its Development and Implementation |url=https://ams.confex.com/ams/97Annual/webprogram/Manuscript/Paper303781/EXTENDED_ABSTRACT_20170228b.pdf |journal=Japan Meteorological Agency}} The scale is also used unofficially in other countries, such as China.{{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=April 2018 |title=Tornado climatology of China |url=https://rmets.onlinelibrary.wiley.com/doi/10.1002/joc.5369 |journal=International Journal of Climatology |language=en |volume=38 |issue=5 |pages=2478–2489 |doi=10.1002/joc.5369 |bibcode=2018IJCli..38.2478C |issn=0899-8418}}

The newer scale was publicly unveiled by the National Weather Service at a conference of the American Meteorological Society in Atlanta on February 2, 2006. It was developed from 2000 to 2004 by the Fujita Scale Enhancement Project of the Wind Science and Engineering Research Center at Texas Tech University, which brought together dozens of expert meteorologists and civil engineers in addition to its own resources.{{cite web |title=Enhanced Fujita Scale - Tornado Damage Scale |url=https://www.factsjustforkids.com/weather-facts/tornado-facts-for-kids/enhanced-fujita-scale.html |access-date=June 14, 2019 |website=factsjustforkids.com}}

The scale was used for the first time in the United States a year after its public announcement when parts of central Florida were struck by multiple tornadoes, the strongest of which were rated at EF3 on the new scale.

In November 2022, a research paper was published that revealed a more standardized EF-scale was in the works. This newer scale is expected to combine and create damage indicators, and introduce new methods of estimating wind speeds in tornadoes. Some of these newer methods include mobile doppler radar and forensic engineering.Marshall, Tim & Brown-Giammanco, Tanya & Krautwurst, Samantha & Toledo, Nicholas. (2022). On the Current Revision of the Enhanced Fujita (EF) Scale.

In 2024, Anthony W. Lyza, Matthew D. Flournoy, and A. Addison Alford, researchers with the National Severe Storms Laboratory, Storm Prediction Center, CIWRO, and the University of Oklahoma's School of Meteorology, published a paper stating, ">20% of supercell tornadoes may be capable of producing EF4–EF5 damage".{{cite journal |last1=Lyza |first1=Anthony W. |last2=Flournoy |first2=Matthew D. |last3=Alford |first3=A. Addison |title=Comparison of Tornado Damage Characteristics to Low-Altitude WSR-88D Radar Observations and Implications for Tornado Intensity Estimation |journal=Monthly Weather Review |date=19 March 2024 |volume=-1 |issue=aop |pages=1689–1710 |doi=10.1175/MWR-D-23-0242.1 |url=https://journals.ametsoc.org/view/journals/mwre/aop/MWR-D-23-0242.1/MWR-D-23-0242.1.xml |access-date=19 March 2024 |publisher=National Oceanic and Atmospheric Administration and University of Oklahoma via the American Meteorological Society |bibcode=2024MWRv..152.1689L |format=Academic publication}}

The seven categories for the EF scale are listed below, in order of increasing intensity. Although the wind speeds and photographic damage examples have been updated, the damage descriptions given are based on those from the Fujita scale, which are more or less still accurate. However, for the actual EF scale in practice, damage indicators (the type of structure which has been damaged) are predominantly used in determining the tornado intensity.

The EF scale currently has 28 damage indicators (DI), or types of structures and vegetation, each with a varying number of degrees of damage (DoD). Each structure has a maximum DoD value, which is given by total destruction. Lesser damage to a structure will yield lower DoD values.{{cite book|last=McDonald|first=James|author2=Kishor C. Mehta|title=A recommendation for an Enhanced Fujita scale (EF-Scale)|publisher=Wind Science and Engineering Research Center, Texas Tech University|date=October 10, 2006|location=Lubbock, Texas|url=http://www.depts.ttu.edu/weweb/Pubs/fscale/EFScale.pdf|access-date=May 21, 2013}} The links in the right column of the following table describe the degrees of damage for the damage indicators listed in each row.

The Enhanced Fujita Scale takes into account the quality of construction and standardizes different kinds of structures. The wind speeds on the original scale were deemed by meteorologists and engineers as being too high, and engineering studies indicated that slower winds than initially estimated cause the respective degrees of damage.Wind Science and Engineering Center. (2006). A recommendation for an enhanced Fujita scale (EF-scale). Retrieved from National Weather Service Storm Prediction Center website https://www.spc.noaa.gov The old scale lists an F5 tornado as wind speeds of {{convert|261|-|318|mph|abbr=on|0}}, while the new scale lists an EF5 as a tornado with winds above {{convert|200|mph|abbr=on|0}}, found to be sufficient to cause the damage previously ascribed to the F5 range of wind speeds. None of the tornadoes in the United States recorded before February 1, 2007, were re-categorized during and after the transition to the EF Scale.

Essentially, there is no functional difference in how tornadoes are rated. The old ratings and new ratings are smoothly connected with a linear formula. The only differences are adjusted wind speeds, measurements of which were not used in previous ratings, and refined damage descriptions; this is to standardize ratings and to make it easier to rate tornadoes which strike few structures. Twenty-eight Damage Indicators (DI), with descriptions such as "double-wide mobile home" or "strip mall", are used along with Degrees of Damage (DoD) to determine wind estimates. Different structures, depending on their building materials and ability to survive high winds, have their own DIs and DoDs. Damage descriptors and wind speeds will also be readily updated as new information is learned. Some differences do exist between the two scales in the ratings assigned to damage. An EF5 rating on the new scale requires a higher standard of construction in houses than does an F5 rating on the old scale. So, the complete destruction and sweeping away of a typical American frame home, which would likely be rated F5 on the Fujita scale, would probably be rated EF4 or lower.{{cite journal |last1=Doswell |first1=Charles A. |last2=Brooks |first2=Harold E. |last3=Dotzek |first3=Nikolai |title=On the Implementation of the Enhanced Fujita Scale in the USA |journal=Atmospheric Research |date=July 2009 |volume=93 |issue=1–3 |pages=556–557 |doi=10.1016/j.atmosres.2008.11.003 |bibcode=2009AtmRe..93..554D |url=https://elib.dlr.de/59709/1/dos.pdf |access-date=20 January 2020}}

Since the EF Scale still uses actual tornado damage and similar degrees of damage for each category to estimate the storm's wind speed, the National Weather Service states that the scale will likely not lead to an increase in the number of tornadoes classified as EF5. Additionally, the upper bound of the wind speed range for EF5 is open—in other words, there is no maximum wind speed designated.

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For purposes such as tornado climatology studies, Enhanced Fujita scale ratings may be grouped into classes.{{cite book | last = Grazulis | first = Thomas P. |author-link = Thomas P. Grazulis | title = Significant Tornadoes 1680–1991 |date=July 1993 | publisher = The Tornado Project of Environmental Films | location = St. Johnsbury, Vermont | isbn = 1-879362-03-1 }}[http://www.tornadoproject.com/fscale/fscale.htm The Fujita Scale of Tornado Intensity] {{webarchive |url=https://web.archive.org/web/20111230005516/http://www.tornadoproject.com/fscale/fscale.htm |date=December 30, 2011 }} at tornadoproject.com{{cite web | url= http://www.nssl.noaa.gov/hazard/ | title= Severe Thunderstorm Climatology | date= March 29, 2013 | publisher= National Severe Storms Laboratory, National Oceanic and Atmospheric Administration, US Department of Commerce | access-date= May 22, 2013 | archive-url= https://web.archive.org/web/20121004084424/http://www.nssl.noaa.gov/hazard/ | archive-date= October 4, 2012 | url-status= dead }} Classifications are also used by NOAA's Storm Prediction Center to determine whether the tornado was "significant". This same classification is also used by the National Weather Service. The National Weather Service of Quad Cities use a modified EF scale wording, which gives a new term for each rating on the scale, going from weak to catastrophic.{{cite web |title=The Tornado Outbreak of March 31, 2023 |url=https://www.weather.gov/dvn/summary_03312023 |publisher=National Weather Service Quad Cities |access-date=21 July 2023}}

The table shows other variations of the tornado rating classifications based on certain areas.

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{{Portal|Weather|Physics}}

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• Beaufort scale
• International Fujita scale
• Lists of tornadoes and tornado outbreaks
• List of F4, EF4, and IF4 tornadoes
• List of F5, EF5, and IF5 tornadoes
• Saffir–Simpson hurricane wind scale
• Severe weather terminology (United States)
• TORRO scale
• Tornado intensity and damage
• Wind engineering

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• {{Cite journal |last=Edwards |first=Roger |author-link= Roger Edwards (meteorologist) |author2=J. G. LaDue |author3=J. T. Ferree |author4=K. Scharfenberg |author5=C. Maier |author6=W. L. Coulbourne |date=May 2013 |title=Tornado Intensity Estimation: Past, Present, and Future |journal=Bull. Amer. Meteor. Soc. |volume=94 |issue=5 |pages=641–53 |bibcode=2013BAMS...94..641E |doi=10.1175/BAMS-D-11-00006.1 |doi-access=free |s2cid=7842905}}

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• National Oceanic and Atmospheric Administration
• [https://www.weather.gov/lsx/enhancedfujitascale NOAA National Weather Service Improves Tornado Rating System] at NOAA News
• [http://www.spc.noaa.gov/efscale/ The Enhanced Fujita Scale (EF Scale)] at Storm Prediction Center
• [http://wdtb.noaa.gov/courses/EF-scale/ EF-Scale Training] {{Webarchive|url=https://web.archive.org/web/20170621062710/http://wdtb.noaa.gov/courses/EF-scale/ |date=June 21, 2017 }} at The Warning Decision Training Branch of National Weather Service (NWS)
• [https://www.spc.noaa.gov/faq/tornado/ef-scale.html The Enhanced Fujita Tornado Scale] at National Climatic Data Center
• [https://repository.library.noaa.gov/view/noaa/7227 The Tornado: An Engineering-Oriented Perspective] (NWS SR147)
• [https://repository.library.noaa.gov/view/noaa/7317 A Guide for Conducting Convective Windstorm Surveys] (NWS SR146)
• [https://web.archive.org/web/20070306232403/http://www.wind.ttu.edu/F_Scale/ Fujita Scale Enhancement Project] (Wind Science and Engineering Research Center at Texas Tech University)
• [http://ams.confex.com/ams/annual2003/techprogram/program_149.htm Symposium on the F-Scale and Severe-Weather Damage Assessment] at American Meteorological Society
• [http://meted.ucar.edu/resource/wcm/ftp/FinalNWSF-scaleAssessmentGuide.pdf A Guide to F-Scale Damage Assessment], MetEd, University Corporation for Atmospheric Research
• [https://web.archive.org/web/20060317202608/http://www.fema.gov/fima/mat/fema342.shtm Mitigation Assessment Team Report: Midwest Tornadoes of May 3, 1999] (Federal Emergency Management Agency)

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