View source for Enhanced Fujita scale

{{Short description|Tornado intensity rating scale}}
{{EF small}}
[[File:The National Weather Service Six-Step Wording for the Enhanced Fujita Scale.jpg|thumb|The [[National Weather Service]]'s arrow showing the EF scale. This includes a description word for each level of the scale.]]

The '''Enhanced Fujita scale''' (abbreviated '''EF-Scale''') is a scale that rates [[tornado intensity]] based on the severity of the damage a tornado causes. It is used in the United States and France, among other countries.<ref>{{cite web | url=https://www.keraunos.org/recherche/comprendre-les-orages-pedagogie-vulgarisation/tornades-trombes-tubas/intensite-tornade-echelle-fujita-amelioree-ef-f-scale.html | title=Intensité des tornades : l'Échelle améliorée de Fujita - Pédagogie - Comprendre les orages - Keraunos - Observatoire français des tornades et orages violents }}</ref> The EF scale is also unofficially used in other countries, including China and Brazil.<ref>{{cite journal | url=https://rmets.onlinelibrary.wiley.com/doi/10.1002/joc.5369 | doi=10.1002/joc.5369 | title=Tornado climatology of China | date=2018 | 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 | journal=International Journal of Climatology | volume=38 | issue=5 | pages=2478–2489 | bibcode=2018IJCli..38.2478C | url-access=subscription }}</ref><ref name="prets">{{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}}</ref> The rating of a tornado is determined by conducting a [[tornado damage survey]]. 

The scale has the same basic design as the original Fujita scale—six intensity categories from zero to five, representing increasing degrees of damage. It was revised to reflect better examinations of tornado damage surveys, in order to align [[wind speed]]s more closely with associated storm damage.  Better standardizing and elucidating what was previously subjective and ambiguous, it also adds more types of structures and [[vegetation]], expands degrees of damage, and better accounts for variables such as differences in construction quality. An "EF-Unknown" (EFU) category was later added for tornadoes that cannot be rated due to a lack of damage evidence.<ref name="EFU">{{cite web |last1=Murphy |first1=John D. |date=26 July 2021 |title=National Weather Service Instruction 10-1605 |url=https://www.weather.gov/media/directives/010_pdfs/pd01016005curr.pdf |access-date=20 April 2025 |publisher=[[National Weather Service]] |pages=A-77–78}}</ref>

As with the Fujita scale, the Enhanced Fujita scale is a damage scale and only an estimate for actual wind speeds. While the wind speeds associated with the damage listed did not and have not undergone empirical analysis (such as detailed physical or any numerical modeling) due to expensive costs, the wind speeds were obtained through a process called [[expert elicitation]], which was based on various engineering studies since the 1970s as well as from the field experience of meteorologists and engineers. Unlike the original [[Fujita scale]] and [[International Fujita scale]], ratings on the Enhanced Fujita scale are based solely off the effects of 3-second gusts on any given damage indicator.<ref name="SPC EF Scale">{{cite web | title = The Enhanced Fujita Scale (EF Scale)| publisher = Storm Prediction Center| date = February 1, 2007| url = http://www.spc.noaa.gov/efscale/| access-date = June 21, 2009 }}</ref>

== History ==
The Enhanced Fujita scale replaced the decommissioned [[Fujita scale]] that was introduced in 1971 by [[Ted Fujita]].<ref>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.</ref> 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.{{notetag|Sources also commonly refer to the CEF-scale simply as the "EF-scale" or "Enhanced Fujita Scale", especially when the context is unambiguously referring to the Canadian version.}}<ref>{{Cite web |title=Fujita Tornado Damage Scale |url=http://www.spc.noaa.gov/faq/tornado/f-scale.html |website=www.spc.noaa.gov}}</ref><ref>{{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 }}</ref><ref>{{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}}</ref><ref>{{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.}}</ref><ref name="IF Scale">{{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}}</ref> 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.<ref>{{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}}</ref> In Brazil, the EF Scale is used by the Reporting Platform and Voluntary Network of Severe Storm Observers ([[PREVOTS]]) since June 2018.<ref name="prets" /> 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.<ref>{{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}}</ref> The scale is also used unofficially in other countries, such as China.<ref>{{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|url-access=subscription }}</ref>

The newer scale was publicly unveiled on October 4, 2004 at the [[American Meteorological Society]]'s 22nd Conference on Severe Local Storms in [[Hyannis, Massachusetts|Hyannis]], Massachusetts.<ref>{{cite web | last = Marshall | first = Timothy P.|title=Session 3B.2 The enhanced Fujita (EF) scale | url=https://ams.confex.com/ams/11aram22sls/webprogram/Paper81090.html | website = ams.confex.com
| publisher = [[American Meteorological Society]]}}</ref> 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 [[meteorologist]]s and [[civil engineer]]s in addition to its own resources.<ref name="FJFK: Fujita Scale - Tornado Damage Scale">{{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}}</ref>

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 [[2007 Central Florida tornadoes|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 [[Doppler on Wheels|mobile doppler radar]] and forensic engineering.

In 2024, Anthony W. Lyza, Matthew D. Flournoy, and A. Addison Alford, researchers with the [[National Severe Storms Laboratory]], [[Storm Prediction Center]], [[Cooperative Institute for Severe and High-Impact Weather Research and Operations|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".<ref name="2024RadarPaper">{{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 publishing|Academic publication]]}}</ref>

==Parameters==
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.<ref name="SPC EF Scale" />
{| class="wikitable"
|-
! rowspan="2" | Scale
! colspan="2" | {{nowrap|Wind speed estimate<ref name="EF SPC">{{cite web | title = Enhanced F Scale for Tornado Damage| publisher = Storm Prediction Center| url = http://www.spc.noaa.gov/efscale/ef-scale.html| access-date = June 21, 2009 }}</ref>}}
! rowspan="2" | Frequency<ref name="SPC WCM">{{cite web |title=Storm Prediction Center WCM Data |url=https://www.spc.noaa.gov/wcm/data/ |archive-url=https://web.archive.org/web/20250407182946/https://www.spc.noaa.gov/wcm/data/ |archive-date=April 7, 2025 |access-date=September 15, 2021 |publisher=Storm Prediction Center}}</ref>
! rowspan="2" | Potential Damage
! rowspan="2" | Example of damage
|-
! mph
! km/h
|-
| align="center" bgcolor="#{{storm color|unknown}}" | <big>'''EFU'''</big>
| style="text-align:center;"| N/A ||  style="text-align:center;"| N/A
| style="text-align:center;"| 3.11%
| {{Anchor|EFU}}No surveyable damage.{{pb}}Intensity cannot be determined due to a lack of information. This rating applies to tornadoes that traverse areas with no damage indicators, cause damage in an area that cannot be accessed by a survey, or cause damage that cannot be differentiated from that of another tornado.<ref name="EFU"/>
| align="center" | N/A
|-
| align="center" bgcolor="#{{storm color|storm}}" | <big>'''EF0'''</big>
| style="text-align:center;"| 65–85 ||  style="text-align:center;"| 105–137
| style="text-align:center;"| 52.82%
| {{Anchor|EF0}}Minor damage.{{pb}}Well-built structures are typically unscathed, though sometimes sustaining broken windows, with minor damage to roofs and chimneys. Billboards and large signs can be knocked down. Trees may have large branches broken off and may be uprooted if they have shallow roots.<ref>{{Cite web|title=Garrett's Blog: Mobile Home Tornado Risk|url=https://www.5newsonline.com/article/weather/garretts-blog-mobile-home-tornado-risk/527-8d21a71a-ca84-4b95-bc1a-b55744b0a2af|access-date=2020-09-30|website=5newsonline.com|date=February 28, 2013|language=en-US}}</ref>
| [[File:Sunset Beach EF0 damage.jpg|150px|EF0 damage example--Well-built structures are typically unscathed, though sometimes sustaining broken windows, with minor damage to roofs and chimneys. Billboards and large signs can be knocked down. Trees may have large branches broken off and can be uprooted if they have shallow roots.]]
|-
| align="center" bgcolor="#{{storm color|cat1}}"  | <big>'''EF1'''</big>
| style="text-align:center;"|  86–110 || style="text-align:center;"| 138–177
| style="text-align:center;"| 32.98%
| {{Anchor|EF1}}Moderate damage. {{pb}}Damage to mobile homes and other temporary structures becomes significant, and cars and other vehicles may be pushed off the road or flipped. Permanent structures can suffer major damage to their roofs.
| [[File:EF1 damage Richardson, Texas.jpg|150px|EF1 damage example--There is damage to mobile homes and other temporary structures becomes significant, and cars and other vehicles can be pushed off the road or flipped. Permanent structures can suffer major damage to their roofs.]]
|-
| align="center" bgcolor="#{{storm color|cat2}}"  | <big>'''EF2'''</big>
| style="text-align:center;"| 111–135 || style="text-align:center;"| 178–217
| style="text-align:center;"| 8.41%
| {{Anchor|EF2}}Considerable damage. {{pb}}Well-built structures can suffer serious damage, including roof loss, and the collapse of some exterior walls may occur in poorly built structures. Mobile homes, however, are destroyed. Vehicles can be lifted off the ground, and lighter objects can become small missiles, causing damage outside of the tornado's main path. Wooded areas have a large percentage of their trees snapped or uprooted.
| [[File:WelchEF2Damage2012.jpg|150px|EF2 damage example--Well-built structures can suffer serious damage, including roof loss, and the collapse of some exterior walls may occur in poorly built structures. Mobile homes, however, are destroyed. Vehicles can be lifted off the ground, and lighter objects can become small missiles, causing damage outside of the tornado's main path. Wooded areas have a large percentage of their trees snapped or uprooted.]]
|-
| align="center" bgcolor="#{{storm color|cat3}}"  | <big>'''EF3'''</big>
| style="text-align:center;"| 136–165 || style="text-align:center;"| 218–266
| style="text-align:center;"| 2.18%
| {{Anchor|EF3}}Severe damage. {{pb}}A few parts of affected buildings are left standing. Well-built structures lose all outer and some inner walls. Unanchored homes are swept away, and homes with poor anchoring may collapse entirely. Trains and train cars are all overturned. Small vehicles and similarly sized objects are lifted off the ground and tossed as projectiles. Wooded areas suffer an almost total loss of vegetation and some tree debarking may occur.
| [[File:January 23, 2012, Center Point, Alabama tornado damage.JPG|150px|EF3 damage example--A few parts of affected buildings are left standing. Well-built structures lose all outer and some inner walls. Unanchored homes are swept away, and homes with poor anchoring may collapse entirely. Trains and train cars are all overturned. Small vehicles and similarly sized objects are lifted off the ground and tossed as projectiles. Wooded areas suffer an almost total loss of vegetation and some tree debarking may occur.]]
|-
| align="center" bgcolor="#{{storm color|cat4}}"  | <big>'''EF4'''</big>
| style="text-align:center;"| 166–200 || style="text-align:center;"| 267–322
| style="text-align:center;"| 0.45%
| {{Anchor|EF4}}Devastating damage. {{pb}}Well-built homes are reduced to a short pile of medium-sized debris on the foundation. Homes with poor or no anchoring are swept completely away. Large, heavy vehicles, including airplanes, trains, and large trucks, can be pushed over, flipped repeatedly, or picked up and thrown. Large, healthy trees are entirely debarked and snapped off close to the ground or uprooted altogether and turned into flying projectiles. Passenger cars and similarly sized objects can be picked up and flung for considerable distances.
| [[File:Tuscaloosa tornado damage 27 April 2011.jpg|left|150x150px|frameless]]
|-
| align="center" bgcolor="#{{storm color|cat5}}"  | <big>'''EF5'''</big>
| style="text-align:center;"| 201+|| style="text-align:center;" | 323+
| style="text-align:center;"| 0.05%
| {{Anchor|EF5}}Incredible damage. {{pb}}Well-built and well-anchored homes are swept cleanly off their foundations and obliterated. Large, steel-reinforced structures such as schools are completely leveled. Low-lying grass and vegetation are shredded from the ground. Trees are completely debarked and snapped. Very little recognizable structural debris is generated with most materials reduced to a coarse, dispersed mix of small, granular particles. Large, multiple-ton steel frame vehicles and farm equipment are often mangled beyond recognition and tossed miles away or reduced entirely to unrecognizable parts. Tall buildings collapse or suffer severe structural deformation. The official description of this damage highlights the extreme nature of the destruction, noting that "incredible phenomena can and will occur".
| [[File:EF5damageMoore2013.jpg|150px|EF5 damage example--Well-built and well-anchored homes are taken off their foundations and they go into the air before obliteration. The wreckage of those homes is flung for miles and those foundations are swept completely clean. Large, steel-reinforced structures such as schools are completely leveled. Low-lying grass and vegetation are shredded from the ground. Trees are completely debarked and snapped. Very little recognizable structural debris is generated with most materials reduced to a coarse mix of small, granular particles and dispersed. Large, multiple-ton steel frame vehicles and farm equipment are often mangled beyond recognition and tossed miles away or reduced entirely to unrecognizable parts. Tall buildings collapse or have severe structural deformations. The official description of this damage highlights the extreme nature of the destruction, noting that "incredible phenomena can and will occur".]]
|}

===Damage indicators and degrees of damage===
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.<ref name="EF-Scale">{{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}}</ref> The links in the right column of the following table describe the degrees of damage for the damage indicators listed in each row.
{| class="wikitable sortable"
|-
! DI No. !! Damage indicator (DI) !! Maximum degrees of damage
|-
| style="text-align:center;"|  1 || Small barns or farm outbuildings (SBO)
| style="text-align:center;"| 8<ref>[[c:File:EF DI1 (SBO).jpg]]</ref>
|-
| style="text-align:center;"|  2 || One- or two-family residences (FR12)
| style="text-align:center;"| 10<ref>[[c:File:EF DI2 (FR12).jpg]]</ref>
|-
| style="text-align:center;"|  3 || Manufactured home – single wide (MHSW)
| style="text-align:center;"| 9<ref>[[c:File:EF DI3 (MHSW).jpg]]</ref>
|-
| style="text-align:center;"|  4 || Manufactured home – double wide (MHDW) || style="text-align:center;"| 12<ref>[[c:File:EF DI4 (MHDW).jpg]]</ref>
|-
| style="text-align:center;"|  5 || Apartments, condos, townhouses [three stories or less] (ACT)
| style="text-align:center;"| 6<ref>[[c:File:EF DI5 (ACT).jpg]]</ref>
|-
| style="text-align:center;"|  6 || Motel (M)
| style="text-align:center;"| 10<ref>[[c:File:EF DI6 (M).jpg]]</ref>
|-
| style="text-align:center;"|  7 || Masonry apartment or motel building (MAM)
| style="text-align:center;"| 7<ref>[[c:File:EF DI7 (MAM).jpg]]</ref>
|-
| style="text-align:center;"|  8 || Small retail building [fast-food restaurants] (SRB)
| style="text-align:center;"| 8<ref>[[c:File:EF DI8 (SRB).jpg]]</ref>
|-
| style="text-align:center;"|  9 || Small professional building [doctor's office, branch banks] (SPB)
| style="text-align:center;"| 9<ref>[[c:File:EF DI9 (SPB).jpg]]</ref>
|-
| style="text-align:center;"| 10 || Strip mall (SM)
| style="text-align:center;"| 9<ref>[[c:File:EF DI10 (SM).jpg]]</ref>
|-
| style="text-align:center;"| 11 || Large shopping mall (LSM)
| style="text-align:center;"| 9<ref>[[c:File:EF DI11 (LSM).jpg]]</ref>
|-
| style="text-align:center;"| 12 || Large, isolated retail building [Wal-Mart, Home Depot] (LIRB)
| style="text-align:center;"| 7<ref>[[c:File:EF DI12 (LIRB).jpg]]</ref>
|-
| style="text-align:center;"| 13 || Automobile showroom (ASR)
| style="text-align:center;"| 8<ref>[[c:File:EF DI13 (ASR).jpg]]</ref>
|-
| style="text-align:center;"| 14 || Automobile service building (ASB)
| style="text-align:center;"| 8<ref>[[c:File:EF DI14 (ASB).jpg]]</ref>
|-
| style="text-align:center;"| 15 || Elementary school [single-story; interior or exterior hallways] (ES)
| style="text-align:center;"| 10<ref>[[c:File:EF DI15 (ES).jpg]]</ref>
|-
| style="text-align:center;"| 16 || Junior or senior high school (JHSH)
| style="text-align:center;"| 11<ref>[[c:File:EF DI16 (JHSH).jpg]]</ref>
|-
| style="text-align:center;"| 17 || Low-rise building [1–4 stories] (LRB)
| style="text-align:center;"| 7<ref>[[c:File:EF DI17 (LRB).jpg]]</ref>
|-
| style="text-align:center;"| 18 || Mid-rise building [5–20 stories] (MRB)
| style="text-align:center;"| 10<ref>[[c:File:EF DI18 (MROB).jpg]]</ref>
|-
| style="text-align:center;"| 19 || High-rise building [more than 20 stories] (HRB)
| style="text-align:center;"| 10<ref>[[c:File:EF DI19 (HROB).jpg]]</ref>
|-
| style="text-align:center;"| 20 || Institutional building [hospital, government or university building] (IB)
| style="text-align:center;"| 11<ref>[[c:File:EF DI20 (IB).jpg]]</ref>
|-
| style="text-align:center;"| 21 || Metal building system (MBS) || style="text-align:center;"| 8<ref>[[c:File:EF DI21 (MBS).jpg]]</ref>
|-
| style="text-align:center;"| 22 || Service station canopy (SSC) || style="text-align:center;"| 6<ref>[[c:File:EF DI22 (SSC).jpg]]</ref>
|-
| style="text-align:center;"| 23 || Warehouse building [tilt-up walls or heavy-timber construction] (WHB)
| style="text-align:center;"| 7<ref>[[c:File:EF DI23 (WHB).jpg]]</ref>
|-
| style="text-align:center;"| 24 || Electrical transmission lines (ETL)
| style="text-align:center;"|6<ref>[[c:File:EF DI 24 (ETL).jpg]]</ref>
|-
| style="text-align:center;"| 25 || Free-standing towers (FST)
| style="text-align:center;"|3<ref>[[c:File:EF DI25 (FST).jpg]]</ref>
|-
| style="text-align:center;"| 26 || Free-standing light poles, luminary poles, flag poles (FSP)
| style="text-align:center;"| 3<ref>[[c:File:EF DI26 (FSP).jpg]]</ref>
|-
| style="text-align:center;"| 27 || Trees: hardwood (TH)
| style="text-align:center;"| 5<ref>[[c:File:EF DI27 (TH).jpg]]</ref>
|-
| style="text-align:center;"| 28 || Trees: softwood (TS)
| style="text-align:center;"| 5<ref>[[c:File:EF DI28 (TS).jpg]]</ref>
|}

==Differences from the Fujita scale==
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.<ref>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</ref> 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.<ref name="EF-Scale"/> 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.<ref>{{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}}</ref>

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.<ref name="SPC EF Scale"/>

==Rating classifications==
{| class="wikitable" style="text-align:center; float:right; margin:0.5em 0 1.3em 1.4em;"
|+ Tornado rating classifications
|-
!Organization
! EF0
! EF1
! EF2
! EF3
! EF4
! EF5
!Cit.
|-
|[[National Weather Service Quad Cities, Iowa/Illinois|NWS Quad Cities, IA/IL]]
| colspan="1" style="background: #{{storm colour|storm}};" | Weak
| colspan="1" style="background: #{{storm colour|cat1}};" | Moderate
| colspan="1" style="background: #{{storm colour|cat2}};" | Significant
| colspan="1" style="background: #{{storm colour|cat3}};" | Severe
| colspan="1" style="background: #{{storm colour|cat4}};" | Extreme
| colspan="1" style="background: #{{storm colour|cat5}};" | Catastrophic
|<ref name="summary_03312023">{{Cite web |last= |first= |date=2023 |title=The Tornado Outbreak of March 31, 2023 |url=https://www.weather.gov/dvn/summary_03312023 |access-date=2025-08-17 |website=National Weather Service Quad Cities, IA/IL |language=EN-US}}</ref>
|-
|[[National Weather Service|NWS]]
| colspan="2" style="background: #{{storm colour|cat1}};" | Weak
| colspan="2" style="background: #{{storm colour|cat3}};" | Strong
| colspan="2" style="background: #{{storm colour|cat5}};" | Violent
|<ref name="sigchitorn" />
|-
|[[National Weather Service|NWS]]
| colspan="2" |
| colspan="4" style="background: #{{storm colour|cat2}};" | Significant
|<ref name="sigchitorn">{{Cite web |last= |first= |title=A Study of the Chicago Areas Significant Tornadoes |url=https://www.weather.gov/lot/sigchitorn |access-date=2025-08-17 |website=National Weather Service |language=EN-US}}</ref>
|}

For purposes such as [[tornado climatology]] studies, Enhanced Fujita scale ratings may be grouped into classes.<ref name="significant tornadoes">{{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 }}</ref><ref>[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</ref><ref>{{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 }}</ref> The National Weather Service classifies EF0 and EF1 as weak, EF2 and EF3 as strong, as EF4 and EF5 as violent.<ref name="sigchitorn" /> The National Weather Service also uses the EF scale to classify tornadoes with a rating of EF2 and greater as significant.<ref name="sigchitorn" /> The [[National Weather Service Quad Cities, Iowa/Illinois]] uses a modified EF scale wording, which gives a new term for each rating on the scale, going from weak to catastrophic.<ref name="summary_03312023" />
==See also==
{{Portal|Weather|Physics}}
{{Div col|colwidth=20em}}
* [[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]]
{{Div col end}}

==Notes==
{{reflist|group=note}}

==References==
{{Reflist}}

==Further reading==
* {{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}}

==External links==
{{Commons}}

* [[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]])
{{EF scale}}
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