The highest rated damage following the 2024 Greenfield tornado; an engineered or well-constructed home with its slab swept clean of debris
Since the late 18th century, meteorologists and engineers have worked to assess the intensity of tornadoes, typically through the work of a tornado damage survey or a scientific case study. This work has led to the creation of the Fujita scale (F-scale) in 1971 and the TORRO scale in 1975. However, the original Fujita scale lacked the incorporation of diverse empirical damage to estimate wind speeds, such as construction quality; to address this, the Enhanced Fujita scale (EF-scale) was created in 2007, followed by the International Fujita scale (IF-scale) in 2023.[1] Despite these efforts to help assess the strength of tornadoes, engineers, scientists and academics have disagreed with each other on how strong various tornadoes were. This is a list of notable disagreements on the intensity of a particular tornado.
A diagram illustrating the relationship between the Beaufort, Fujita, and Mach number scales
The Fujita scale was the first method to systematically rate tornadoes based on damage assessment. It linked damage descriptions—like felled trees or destroyed houses—to a bracket of wind speeds that would have been necessary to cause the damage, assigning each a rating from F0 to F5. This approach to rating tornadoes and concluding their probable wind speeds was revolutionary and was replicated and adapted into the various scales used today.[2] These evaluations are significantly affected by the subjectivity of individual survey teams, however; slight differences in interpretation can lead to markedly different ratings even for the same event. Furthermore, separate damage scales used in different countries have a bias towards certain construction types. The Enhanced Fujita scale, for instance, was constructed based on the United States' construction standards, whereas the TORRO scale implicitly reflects British construction standards and ultimately ties back to the Beaufort scale.[3]
It is often difficult to distinguish tornadoes in the upper echelons of the Fujita scale as minute details must be analyzed in order to provide an accurate rating. Conversely, tornadoes which leave behind little to no damage can not be accurately represented using damage assessment methods.[4] Tornadoes that happened farther in the past or in regions outside of more tornado-prepared areas will have similar difficulty in receiving an accurate rating due to a dearth of information. The situation is further muddled by the fact that these scales incorporate different types of data, leading to differing ratings based on which scale is used. For example, the International Fujita scale uniquely uses measured wind speeds via Doppler weather radar alongside damage assessment techniques.[5] This variation in the interpretation of damage and in the methodology by which to categorize it often causes engineers and scientists alike to disagree on the strength of tornadoes.
The severity of this epic storm has been disputed by the meteorological community for several decades. Official observations classified this tornado as F4, but damage was consistent with an F5 tornado in five of the affected towns (Rutland, Holden, Worcester, Shrewsbury and Westborough). As a result of this debate, the National Weather Service took an unprecedented step and convened a panel of weather experts during the spring of 2005 to study the latest evidence on the wind strength of the Worcester tornado. The panel considered whether to raise its designation to F5, but decided during the summer of 2005 to keep the official rating as a strong F4. The reasoning for this was that the anchoring techniques used in many of the destroyed or vanished homes could never be ascertained with certainty now, and some of these structures (many of recent postwar construction) were possibly more vulnerable to high winds than older homes. Without a proper engineering qualification, it would be nearly impossible to determine with 100% accuracy which damage was F5 and which was F4, as appearances would be similar.[citation needed]
Aerial view of the Sunnyside subdivision in Dunlap, Indiana, after the tornado
On April 11, 1965, a violent tornado struck the cities of Elkhart and Goshen, as well as the community of Dunlap in Indiana. The tornado completely destroyed the Sunnyside subdivision and the Kingston Heights subdivision in Dunlap. Following the creation of the Fujita scale in 1971, the National Weather Service office in Northern Indiana rated the worst of the damage F5. However, after further analysis, this rating was officially downgraded to F4.[14] Tornado expert Thomas P. Grazulis rated the tornado F5 in 1993.[11] In 2000, the National Oceanic and Atmospheric Administration along with the Nuclear Regulatory Commission rated the tornado F5.[15]
On April 11, 1965, a violent tornado struck the towns of Lebanon and Sheridan in Indiana. Following the creation of the Fujita scale in 1971, the National Weather Service office in Northern Indiana rated the worst of the damage near Lebanon and Sheridan F4, stating the tornado "may have been an F5".[14] In 2000, the National Oceanic and Atmospheric Administration along with the Nuclear Regulatory Commission rated the tornado F5.[15]
On April 11, 1965, a violent tornado struck the towns of Pittsfield, Grafton, LaGrange, and Strongsville in Ohio. Homes were cleanly swept away in Strongsville and Pittsfield, and Pittsfield was completely destroyed. Only a concrete war monument remained standing in Pittsfield, where homes "vanished." Following the creation of the Fujita scale in 1971, the National Weather Service office in Northern Indiana rated the worst of the damage F4. Tornado expert Thomas P. Grazulis rated the tornado F5 in 1993.[11] In 2000, the National Oceanic and Atmospheric Administration along with the Nuclear Regulatory Commission rated the tornado F5.[15]
On May 11, 1970, a powerful multi-vortex tornado struck the city of Lubbock, Texas. The tornado, in its time the costliest tornado in U.S. history, causing an estimated $250million in damage (equivalent to $1.96billion in 2023), damaging nearly 9,000homes and inflicting widespread damage to businesses, high-rise buildings, and public infrastructure. The tornado's damage was surveyed by meteorologist Ted Fujita in what researcher Thomas P. Grazulis described as "the most detailed mapping ever done, up to that time, of the path of a single tornado." Originally, the most severe damage was assigned a preliminary F6 rating on the Fujita scale, making it one of only two tornadoes to receive the rating, alongside the 1974 Xenia tornado. Later, it was downgraded to an F5 rating. The extremity of the damage and the force required to displace heavy objects as much as was observed indicated that winds produced by vortices within the tornado may have exceeded 290mph (470km/h).[16][17][18][19][11]
On April 3, 1974, amid the 1974 Super Outbreak, a violent tornado struck several towns in Lincoln County, Franklin County, and Coffee County in Tennessee. The worst of the damage in Franklin County was rated F5 by the National Weather Service, however, in March 2012, the National Weather Service stated they could not confirm if the United States Weather Bureau ever conducted a damage survey after the tornado.[11][27][28] Professor Ted Fujita and several of his graduate students did conduct a damage survey, where they "were unable to locate the reference to 'incredible damage' that results from an F5" rating. After their survey and analysis, Fujita and his students sent a letter to the Storm Prediction Center, recommending the tornado be downgraded to an F4 rating. Following this letter, the National Weather Service downgraded the tornado to an F4 rating.[11][27]
1979 Cheyenne tornado
On July 16, 1979, an intense tornado struck Cheyenne, Wyoming. The worst of damage was rated F3 by the National Weather Service office in Cheyenne.[29] However, in May 1980, William T. Parker and Richard D. Hickey, meteorologists at the National Weather Service office in Cheyenne published a case study on the tornado. In the study, they stated "F4 damage was found in a portion of the Buffalo Ridge housing area where large two-story, single family houses were reduced to foundations surrounded and covered by debris." The researchers also stated the path width of the F4 damage area was 220 metres (240yd).[30]
On June 9, 1984, an unusually significant tornado outbreak took place that saw a violent tornado strike the cities of Ivanovo and Lunyovo in the eastern Soviet Union (now Russia). One particularly devastating multiple vortex tornado touched down south of Ivanovo, travelling north-northeast as it snapped swaths of birch, spruce, and pine trees.[31] The tornado tossed aside a large crane which weighed 320,000 kilograms (710,000 pounds) and lofted an elevated water tank that weighed 50,000 kilograms (110,000 pounds) a distance of over 200 metres (0.12mi).[32][33] The northern suburbs of Ivanovo, consisting of many wooden summer homes, were flattened, with other structures being completely obliterated or swept away to their foundations. Numerous trees were denuded, debarked, or uprooted. Cars at this location were rendered unrecognizable.[34][35] Researchers disagree on the intensity of the tornado, with some estimating it had an F4 rating and others believing it deserved an F5 rating. In fact, the Ivanovo tornado was originally classified as an F5 before the ESSL recategorized it as an F4 in 2018.[32]
1990s
1990 Bakersfield Valley tornado
On June 1, 1990, a large, violent, multi-vortex tornado struck rural parts of Pecos County, Texas, including the ranching community of Bakersfield Valley. A well-engineered adobe brick home was destroyed by the tornado at F4 intensity. A 300-foot section of asphalt was scoured from a road, as well as nearby suction marks and an 8 mile long by half mile wide swath of scoured vegetation were noted by the surveyors. This damage was also rated as F4. After decreasing in intensity slightly and causing two fatalities in pickup trucks, the tornado restrengthened and struck the Yates Oil Field, where 57 oil pumps and other equipment were damaged or destroyed. Most notably at this location, three full 500-barrel oil tanks, weighing approximately 70 tons each, were broken free from a tank battery and rolled for more than 3 miles across a field and pushed up a hill. Damage at the oil field earned an F4 rating. Surveyors noted that the tornado produced damage not seen in the Saragosa tornado three years prior, such as the asphalt scouring and the extensive vegetation scouring. They also suspected that the Bakersfield Valley tornado was stronger than the Saragosa tornado at times, but the evidence was insufficiently conclusive to warrant an F5 rating.[36][37]
On June 8, 1995, an extremely severe and localized outbreak of tornadoes occurred in the Texas Panhandle. Officially rated F4, a violent stovepipe tornado struck the city of Pampa, Texas after touching down to its southwest. Its short path length and lack of damage to structures limited its rating. Per Thomas P. Grazulis, the F4 rating given was based on the movement of industrial equipment, as the tornado had weakened significantly by the time it entered more populated areas. Grazulis used photogrammetry to conclude that at about 100 feet above ground level, the tornado had wind speeds in the 200–250 miles per hour, not counting a powerful vertical wind component.[38] Grazulis later discussed the Pampa event in F5-F6 Tornadoes and declared "In my opinion, if there ever was an F6 tornado caught on video, it was the Pampa, Texas tornado of 1995".[39] The same supercell responsible for the Pampa tornado cycled and produced another significant tornado near Hoover, Texas, which was officially rated F2. Narrowly missing the Jordan Unit prison, this tornado displayed significant strength by stripping asphalt from the local highways.[40] Storm chasers who saw the event concur that this tornado is underrated, with Martin Lisius rating it as an F5 tornado.[41]
An hour after the Hoover tornado lifted, a second significant supercell formed near Clarendon, Texas. After producing three F2 tornadoes, the storm cycled and produced a violent tornado near the community of Kellerville, tracking northeast. Significant ground scouring was documented along its unusually sinusoidal damage track, and winds exceeding 110m/s (246mph, 396km/h) were recorded by Doppler radar.[42] Asphalt was stripped from roads and several structures were destroyed, including some swept away from their foundations. The extraordinary damage and high recorded wind speeds leads researchers and storm chasers alike to attest that the Kellerville tornado had attained F5 strength.[43][44] The same supercell responsible for the Kellerville tornado cycled and formed a violent tornado to the west of Allison, Texas. The tornado initially moved to the northeast at around 60 miles per hour with a maximum width of 1.25 miles before slowing significantly, turning to the west, and occluding similar to the tornado before it. The tornado avoided the town but killed hundreds of livestock in Wheeler County. Despite every spotter report listing the tornado as an F5, the National Weather Service rated it an F4 due to a lack of structural interactions.[45]
Law enforcement searching through debris of a house swept clean off its foundation, shortly after the passing of the tornado
On April 28, 2002, a violent and fast-moving tornado struck the town of La Plata, Maryland. The tornado was initially rated F5 by the National Weather Service office in Baltimore/Washington, but it was downgraded in a secondary damage survey. For a small period of time, this made it the easternmost F5 tornado in the United States. This preliminary F5 rating, partly due to damage to a brick building in downtown La Plata, was lowered to F4 after the damage assessment team determined that some of the damage was due to flying debris from a lumber company nearby. Damage to houses initially rated F5 were lowered when engineer Timothy Marshall surveyed and determined these homes were not properly anchored, causing them to be swept off their foundations by lesser winds. While impressive, team members agreed that the tornado damage was not as intense as other F5 rated tornadoes such as the ones that struck Plainfield, Jarrell, Bridge Creek-Moore, or Andover.[46] Many of the destroyed buildings or "slider homes" were only rated F1 to F3, with surveyors having to depend some ratings solely on the severity of the surrounding damage.[47] This includes the toppled steel water tower in La Plata, which "was impressive but occurred in an area of F1 damage". This event showcased some of the prime issues with using the Fujita scale and is largely responsible for the how tornadoes are surveyed today.[48][49]
On June 22, 2007, a small but powerful tornado struck the southwestern part of Elie, Manitoba. The next day, a preliminary damage assessment by Environment Canada concluded that out of the four houses destroyed by the tornado, the most damaged house received an F4 rating. While they did initially consider rating the tornado as an F5, the lack of any previous F5-rated tornadoes in Canada resulted in the lower rating. Additionally, the investigators were concerned about the scrutiny they would receive from the media and meteorological community if they rated the tornado an F5, and how they could not confirm whether the extreme damage was a result of the tornado's slow motion. In September 2007, Environment Canada officially upgraded the tornado's rating from F4 to F5 based on video evidence and a second damage survey. The videos showed that not only did the tornado remain over each house for no longer than 30 seconds, but also that it showed how exactly the well-built homes were torn their foundations.[50][51]
In 2008 at the American Meteorological Society's 24th Conference on Severe Local Storms, Patrick J. McCarthy, along with D. Carlsen and J. Slipec, submitted a paper for and hosted a presentation on the Elie tornado.[52] At the conference, it was presented that some of the damage did point to an F5 rating, however, the survey team was concerned the tornado was weaker than F5 strength, and only caused the extreme damage due to moving slowly, where it could have "relentlessly pounded the houses into a higher level of destruction".[52] After further investigation using video evidence captured by people watching the tornado, the surveyors determined that "the structural failures were quick. The structural assessments indicated that the homes were well-built and generally well-secured. In particular, one of the destroyed homes met all of the requirements for the highest damage rating."[52] The team also noted that the damage would have qualified for an EF5 rating on the Enhanced Fujita scale, which was in use in the United States at the time.[53]
Tremendous ground scouring left behind by the tornado; a large, debarked, and defoliated tree that was ripped out by its roots and thrown can also be seen in the background
In October 2024, mechanical engineer Ethan Moriarty analyzed the tornado's damage in comparison to non-EF5 tornadoes. Moriarty noted that based on justifications from various National Weather Service offices on other tornadoes, the EF5 rating for the tornado could be "nullified".[56] On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society regarding the EF5 drought. In the paper, the researchers stated the justification for the EF5 rating was a single frame home that was swept away, "within the context of extreme ground scouring (2 feet (0.61m)-deep trench) and a mobile home tossed about 300 yards (270m)."[57] The researchers stated this reasoning was directly given to them by the National Weather Service Jackson, Mississippi office and from Alan Gerard with the National Severe Storms Laboratory, through personal communication in 2024.[57]
EF5 damage in Phil Campbell, with multiple homes swept away and grass scoured from hillsides
On April 27, 2011, amid the 2011 Super Outbreak, a large and long-lived tornado struck several towns in rural northern Alabama before tearing through the northern suburbs of Huntsville; in particular the towns of Hackleburg, Phil Campbell, and Tanner in Alabama. The National Weather Service offices in Birmingham and Huntsville, Alabama, rated the worst of the damage caused by the tornado EF5 with winds estimated to be at least 210 miles per hour (340km/h). Nearly two-dozen locations along the tornado's track were rated EF5.[58][59]
In October 2024, mechanical engineer Ethan Moriarty analyzed the tornado's damage in comparison to non-EF5 tornadoes. Moriarty noted that based on justifications from various National Weather Service offices on other tornadoes, the EF5 rating for the Hackleburg–Phil Campbell tornado could be "nullified".[56] On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society regarding the EF5 drought. In the paper, the researchers stated the justification for the EF5 rating was numerous homes that were swept away, however, only a single home was "bolted to its foundation". The researchers also noted that in Hackleburg, the National Weather Service office in Birmingham, Alabama, used "the tossing of vehicles 150–200 yards (140–180m) and the wind rowing of debris" as contextual reasons to apply the EF5 rating. The researchers went on to state how "only one home was explicitly noted to have actually been anchored to its foundation", and the only location to warrant an EF5 rating.[57]
The tornado in downtown TuscaloosaThe destroyed Chastain Manor apartment complex near Alberta City, Tuscaloosa
On April 27, 2011, amid the 2011 Super Outbreak, a violent multi-vortex tornado destroyed portions of Tuscaloosa and Birmingham, Alabama, as well as smaller communities and rural areas between the two cities. The National Weather Service office in Birmingham, Alabama rated the worst of the damage caused by the tornado EF4 with winds of at least 190 miles per hour (310km/h).[60]
The Chastain Manor Apartments, which were nailed, rather than bolted to their foundations, were completely destroyed and partially swept away by the tornado in the outskirts of Tuscaloosa. A well-anchored clubhouse on the property was mostly swept away and its remains were scattered into a pond, even though the structure had lacked interior walls. A nearby manhole cover was removed from its drain and thrown into a ravine.[60][61][62] The suburbs of Concord, Pleasant Grove, and McDonald Chapel, along with residential areas in northern Birmingham itself, were also devastated by the tornado. Extensive wind-rowing of debris was noted in Concord and Pleasant Grove, numerous trees were debarked, and some homes were swept away, although much of the debris remained next to the foundations and was not scattered, and most vehicles were not moved more than 15 yards (14m). As the tornado moved across a coal yard in this area, a 35.8-tonne (78,925lb) coal car was thrown 391ft (119m) through the air.[62]
The final rating of this tornado was a source of controversy, as some survey teams concluded EF5 damage, while others did not.[63] The structures that were swept away by this tornado were either improperly anchored, lacked interior walls, or were surrounded by contextual damage not consistent with winds exceeding 200mph (320km/h), and as a result an EF5 rating could not be applied. Therefore, it was given a final rating of high-end EF4, with winds estimated at 190mph (310km/h).[60][64][65][66] President Barack and First LadyMichelle Obama visited Tuscaloosa on April 29, taking a ground tour of some of the affected areas. Obama was quoted as saying that he had "never seen devastation like this."[67]
On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society, where they stated the tornado in Tuscaloosa was an "EF5 candidate". It was also explained that the EF5 starting wind speed should be 190 miles per hour (310km/h) instead of 201 miles per hour (323km/h).[57]
On April 27, 2011, amid the 2011 Super Outbreak, a a large and violent tornado struck areas in DeKalb County, Alabama and Dade County, Georgia, particularly around the communities of Shiloh, Rainsville, and Henagar. The National Weather Service office in Huntsville, Alabama, rated the worst of the damage EF5 with winds of at least >200 miles per hour (320km/h), with numerous locations being rated EF5.[68] The National Weather Service rated a "corridor from CR 515 through a neighborhood along County Road 441" as "near EF-5".[68] In that area, numerous one- and two-story homes were leveled to their foundation with debris scattered, cars were thrown large distances, and some sidewalk pavement was pulled up out of the ground by the tornado. "However, some of the homes in this area appeared to be pushed off their foundation initially with limited anchorage. Thus, the damage was deemed high end EF-4 in this area."[68]
In October 2024, mechanical engineer Ethan Moriarty analyzed the tornado's damage in comparison to non-EF5 tornadoes. Moriarty noted that based on justifications from various National Weather Service offices on other tornadoes, the EF5 rating for the Rainsville tornado could be "nullified".[56] On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society regarding the EF5 drought. In the paper, the researchers stated the justification for the EF5 rating was a single location where a large, two-story brick home that was "blown off of its foundation, with several anchors pulled out of the ground and a 800 pounds (360kg), anchored safe found 600 feet (180m) away with its door ripped off."[57]
"The EF-5 rating was mainly arrived at by the total destruction of vehicles of various sizes and weight. Some vehicles were tossed several blocks, and owners were never able to locate their vehicles. Also, parking stops weighing over 300 pounds and re-barred into asphalt were tossed from 20 to 60 yards. Other factors included was the deflection, deformed and tossing of reinforced concrete porches and slabs, and the fact the St. John’s hospital building structure and foundation were compromised and will need to be torn down, were probably caused by winds speed at or exceeding 200 mph."
In 2013, the American Society of Civil Engineers published a study disputing the tornado's initial EF5 rating, based on surveying damage on over 150 structures within a six-mile segment of the storm's path. According to the report, over 83% of the damage was caused by wind speeds of 135mph (217km/h) or less, the maximum wind speed of an EF2 tornado. An additional 13% was caused by EF3 wind speeds, and 3% was consistent with EF4 winds. The study found no damage consistent with wind speeds over 200mph (320km/h), the minimum threshold of an EF5 tornado.[70] Researchers concluded that the inability to find EF5 damage was due to the absence of construction standards that were able to determine the necessary wind speeds. Bill Colbourne, a member of the engineering team that surveyed the damage, declared that "a relatively large number of buildings could have survived in Joplin if they had been built to sustain hurricane winds."
A United States Army Corps of Engineers map shows the tornado's damage path as it moved nearly due east through Joplin, with the most intense damage near its centerline
However, the EF5 rating stood. The NWS office in Springfield stated that their survey teams found only a small area of EF5 structural damage, and that it could have easily been missed in the survey (at and around St. John's Medical Center).[71] Bill Davis, head of Springfield's NWS office, said that the results of the study "do not surprise me at all," adding that "there was only a very small area of EF5 damage in Joplin...we knew right off the bat there was EF4 damage. It took us longer to identify the EF5 damage and that it would take winds of over 200mph (320km/h) to do that damage."[72] Additionally, the basis for the EF5 rating in Joplin was mainly contextual rather than structural, with non-conventional damage indicators such as the removal of concrete parking stops, manhole covers, reinforced concrete porches, driveways, and asphalt used to arrive at a final rating. The presence of wind rowed structural debris, instances of very large vehicles such as buses, vans, and semi-trucks being thrown hundreds of yards to several blocks from their points of origin, the fact that some homeowners never located their vehicles, and the overwhelming extent and totality of the destruction in Joplin were also taken into consideration.[69]
According to a detailed damage survey by Timothy P. Marshall, a majority of houses were destroyed at winds of EF2-3 strength. However he identified 22 well anchored houses which were assigned EF5 ratings.[73]
On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society regarding the EF5 drought. In the paper, the researchers stated the justification for the tornado's EF5 rating was initially 22 homes that were completely swept away, with only the concrete slab remaining. The paper then stated the aforementioned study by the ASCE which "found none of these to actually be EF5". It is then noted a 2012 study published by Christopher D. Karstens, Timothy P. Marshall, and two others which stated, "that the movement of parking stops likely justifies keeping the rating."[57][74]
Damage at the Cactus 117 oil drilling rig near El Reno, showing the mangled and overturned rig
On May 24, 2011, a long-track and extremely powerful tornado struck the areas near or within the communities of El Reno, Piedmont, and Guthrie. Not long after touching down, the tornado struck the Cactus 117 oil drilling rig site, completely destroying it. When it hit, the rig's pipes and drill head were inserted deep in the well's borehole, which provided the drilling pipe with 200,000lb (91,000kg) of downforce.[75]:6 Despite this, and despite the fact that the drilling rig weighed 862 metric tons—or almost two million pounds—the rig was toppled onto its side and rolled several times. The well's blowout preventer was left bent at a 30-degree angle to the north. Elsewhere on the site, vehicles and cargo containers were lofted into the air and tossed.[76]:2[75]:6 Twelve workers were on the site when the tornado struck, and took shelter in the site's change house (a steel container serving as a locker room). Tied down by four steel cables anchored 5.5 feet (1.7m) deep in the ground, the container was pummeled with debris. One cable broke and the container was dented, but all twelve workers survived without serious injury.[75][76]
Despite not being an official damage indicator on the Enhanced Fujita scale, the National Weather Service Norman, Oklahoma rated the damage to the Cactus 117 oil drilling rig EF5 with winds of at least 210 miles per hour (340km/h); the only damage caused by the tornado to receive an EF5 rating.[77][75][76]Mechanical engineer Ethan Moriarty noted in 2023 that changes in procedures with how the EF-scale is applied in the 2020s, a single damage indicator would not be enough to rate the tornado as a whole EF5.[56]
The RaXPol mobile Dopper radar, shown here scanning a severe thunderstorm in Oklahoma in 2013
Prior to striking the oil drilling rig, the tornado was being monitored by a truck-mounted Rapid-Scan X-band Polarimetric (RaXPol) mobile Doppler weather radar, operated by the University of Oklahoma's Advanced Radar Research Center (ARRC) led by Howard Bluestein. That radar, stationed near the intersection of Smith Road and Walbaum Road less than two miles (3.2km) south of I-40, captured the "first polarimetric, rapid-scan, mobile Doppler weather radar dataset of an EF-5 tornado."[78]:3 As the tornado moved towards I-40 to the southeast of the RaXPol radar, it detected some of the fastest wind speeds ever measured on the planet. Interpretations slightly differ: the maximum instantaneous radial velocity sampled by the radar was originally reported as having been 124.8m/s (279mph), measured 200–230 feet (60–70m) above the ground at 4:00:26p.m.;[79]:4103[78]:3[76]:2 however, the maximum velocity was later reported as having been 132.1m/s (295mph) measured ~72 feet (22m) "above radar level" at 4:00:39p.m. in a 2014 paper by Bluestein et al. on the use of radar data for tornado ratings.[80]:811 Maximum radial velocities were also reported to have remained "greater than 120.0m/s (268mph) for several minutes."[76]:2 Additionally, multiple consecutive radar scans were averaged to yield an estimated 2-second average radial velocity of 118.4m/s (265mph) and an estimated 4-second average velocity of 110.8m/s (248mph). This was reported as "likely to be an underestimate of the true 2- and 4-s average wind speeds."[80]:3b
The instantaneous velocity readings taken are not directly equivalent to the three-second gust at 33 feet (10m) that the Enhanced Fujita scale attempts to estimate, but they mark the second-highest wind speed ever recorded in a tornado, after wind speeds of approximately 135m/s (300mph) were recorded in both the 1999 Bridge Creek–Moore tornado[78] and a sub-vortex within the 2013 El Reno tornado.[80][81] Where the most intense winds are generally present in a tornado is an unresolved question, but the limited existing research suggests that wind speeds are likely to be highest closer to the ground.[82][80]:804
On March 2, 2012, a large, long-tracked tornado struck the communities of New Pekin, Henryville, Marysville and Chelsea, Indiana. On March 6, the National Weather Service Louisville, Kentucky rated the worst of the damage EF4 with winds of 175 miles per hour (282km/h).[83] A decade later in 2022, the National Weather Service office in Louisville referred to a possible EF5 damage location at a demolished house, where a pickup truck was blown away and never found and a backhoe was deposited into the basement of the house.[84]
The tornado as it was approaching the city of MooreMeteorologist Tim Marshall surveys a neighborhood that was devastated
On May 20, 2013, a large and violent tornado struck Moore, Oklahoma and surrounding areas. Less than 24 hours after the tornado, on May 21 at 1:10 PM CDT, the National Weather Service Norman, Oklahoma (NWS Norman), rated the tornado EF4 with winds of at least 190 miles per hour (310km/h).[85] At 2:50 PM CDT, less than 24 hours since the tornado had touched down, the NWS Norman upgraded the tornado's rating to EF5 with winds of 200–210 miles per hour (320–340km/h).[86] Shortly after the tornado, the Associated Press stated that the power of the Moore tornado "dwarfs" the atomic bombing of Hiroshima by "8 times to more than 600 times".[87] The tornado's rating was officially finalized as EF5 with winds of 210 miles per hour (340km/h).[88]
Prior to hitting Moore, the tornado struck the Orr Family Farm and the Celestial Acres horse training area. Every building at Celestial Acres was either leveled or swept away at EF4intensity, the ground on the property was scoured to bare soil, debris from structures was granulated, and vehicles were thrown and stripped down to their frames. Surveyors noted that based on the contextual damage, the tornado was likely at EF5intensity in this area, though the construction quality of the affected buildings only permitted an EF4rating.[89][90]
The tornado then heavily scouring an open grassy field before impacting Briarwood Elementary School, which was completely destroyed. The NWS Norman originally rated this damage EF5, but further evaluation and a 2014 study published by the American Meteorological Society revealed evidence of poor construction at the school, and the rating was downgraded to EF4.[89][91] Two 12,000-gallon water tanks that were also swept off of the Orr Family Farm grounds were thrown into this area; the roof of Briarwood Elementary was struck by one of them − potentially aiding in compromising the building's structural integrity as it bent the steel girders that held up the roof − shortly before the main vortex struck the building, while the other fell onto and destroyed a home a few blocks east of the school.[92]
As the tornado entered western Moore, an anchor-bolted home that was reduced to a bare slab in this area was initially rated EF5 by the NWS Norman, but was later downgraded to EF4 as closer inspection of the foundation revealed that the anchor bolts were missing their nuts and washers.[77] The tornado then destroyed Plaza Towers Elementary School at EF4 intensity, where seven children were killed when a cinder block wall collapsed on top of them. More than a dozen homes in a subdivision just to the south of Plaza Towers Elementary were swept cleanly away, though they were revealed to have been nailed rather than bolted to their foundations, and damage to this subdivision was subsequently rated EF4, though the tornado was likely violent as lawns in this area were completely scoured down to bare soil.[89][90][77]
Extreme vehicle damage and ground scouring at the Celestial Acres horse training area
A preliminary study of Briarwood Elementary School conducted in September 2013 by a group of structural engineers found some structural deficiencies that led to its collapse during the tornado. Chris Ramseyer, a structural engineer and an associate professor at the University of Oklahoma determined that the building's walls that were not reinforced with concrete, there had been a lack of connection between the masonry walls and support beams in several portions of the building, and anchor bolts were pulled from the ground by the tornado. Another engineer that was involved in the study stated that the deficiencies that Ramseyer pointed out were not uncommon building practices at the time, and that current building code standards would not ensure that Briarwood would have withstood winds in excess of 200 miles per hour (320km/h).[93]
On May 20, 2023, mechanical engineer Ethan Moriarty analyzed the tornado's damage; specifically, the steel propane tank thrown from the Orr Family Farm that flew over the Briarwood Elementary School, landing on a nearby house. In his analysis, Moriarty determined winds of approximately 209 miles per hour (336km/h) were needed to throw the propane tank.[94] In October 2024, Moriarty analyzed the tornado's damage in comparison to non-EF5 tornadoes. Moriarty noted how telephone poles were barely leaning only 80 yards (73m) away from one of the locations which received an EF5 rating, which was similar to why the 2014 Mayflower–Vilonia tornado was only rated EF4 and not EF5 due to nearby small trees that were still standing near the worst of the damage.[56]
View of the tornado as it was nearing peak strengthVideo of several sub-vortices within the tornado
On May 31, 2013, an extremely large, powerful, and erratic tornado struck around El Reno, Oklahoma. The tornado grew to an unprecedented width of 2.6 miles (4.2km), becoming the officially widest-known tornado ever recorded in history. The intensity of the tornado has been a subject of internal debate within the National Oceanic and Atmospheric Administration. The agency uses the Enhanced Fujita Scale to rate and assess tornado intensity based on the damage left behind. This excludes the use of supplementary measurements, such as those from mobile radar, in concluding a tornado's intensity.[95] Initially receiving an official EF3 rating based on damage, the El Reno tornado was subsequently upgraded to a radar-estimated EF5 rating, the highest on the scale, based on data from a mobile radar. The University of Oklahoma's RaXPol mobile Doppler weather radar, positioned at a nearby overpass, measured winds preliminarily analyzed as in excess of 296mph (476km/h). These winds are considered the second-highest ever measured worldwide, just shy of the 321mph (517km/h) recorded during the 1999 Bridge Creek–Moore tornado.[96][97]
Revised RaXPol analysis found winds of 302±34mph (486±55km/h) well above ground level and ≥291mph (468km/h) below 10m (33ft), with some subvortices moving at 175mph (282km/h).[98] The strongest winds occurred in small subvortices along the south side of the main vortex. The two most intense vortices occurred north and east of the intersection of 10th Street and Radio Road, about 3 miles (4.8km) southeast of El Reno.[99][100] The main funnel is believed to have had radar-estimated EF4 winds, with wind speeds around 185mph (298km/h). Radar-estimated EF5 winds were only found aloft and in the smaller vortices that revolved around this funnel at 110mph (180km/h).[96] A revised analysis in 2015 revealed a peak wind of 313mph (504km/h).[101] In March 2024, NOAA and OU published a new analysis, which estimated that winds may have reached up to anywhere between 115–150m/s (257–336mph; 414–540km/h).[102]
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Rick Smith, the warning coordination meteorologist at the National Weather Service Weather Forecast Office in Norman, stated that this tornado was among a "super-rare" category within the EF5 rating. Smith also stated that it was fortunate the tornado did not track into more densely populated areas, particularly those within the Oklahoma City metropolitan area, "this would have been … I don't even want to imagine what it would have been."[99] William Hooke, a senior policy fellow at the American Meteorological Society stated that, "[Oklahoma City] dodged a bullet...You lay that path over Oklahoma City, and you have devastation of biblical proportions."[103]
On August 30, the National Weather Service office in Norman once again revised the intensity of the El Reno tornado. Keli Pirtle, a Public Affairs worker at the National Oceanic and Atmospheric Administration, stated that, "despite the radar-measured wind speeds, the survey team did not find damage that would support a rating higher than EF3. While the wind measurements from the mobile radars are considered reliable, NWS policy for determining EF-ratings is based on surveys of ground damage."[95] The lack of EF5 damage was likely a result of the rural nature of the area, as the sub-vortices that contained the EF5 wind speeds did not impact any structures.[104][105]
On April 27, 2014, a large and destructive tornado struck towns of Paron, Mayflower, Lake Conway, Vilonia and El Paso in Arkansas. The National Weather Service rated the worst of the damage caused by the tornado EF4 with winds of at least 190 miles per hour (310km/h). The final rating of the tornado was a source of controversy, and the National Weather Service office in Little Rock, Arkansas, 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.[106] The new scale accounts for homes that use cut nails instead of anchor bolts, which do not effectively provide resistance against violent tornadoes.[107]
Aerial view of high-end EF4 damage in Vilonia
The final decision on an EF4 rating was based on this as well. However, meteorologist, structural and forensic engineerTimothy 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."[90][107] 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.[107]
On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society, where they stated the tornado in Vilonia was an "EF5 candidate". It was also explained that the EF5 starting wind speed should be 190 miles per hour (310km/h) instead of 201 miles per hour (323km/h).[57]
On June 16, 2014, a powerful cyclic supercell struck northeast Nebraska, producing six tornadoes, including four violent tornadoes. One of the violent tornadoes, often referred to as the main Pilger twin tornado, destroyed a well-built farmhouse. The National Weather Service office of Omaha/Valley, Nebraska, rated the damage to the farmhouse EF4 with winds of 191 miles per hour (307km/h).[77] On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society, where they stated the main Pilger twin tornado was an "EF5 candidate", specifically at the aforementioned farmhouse. It was also explained that the EF5 starting wind speed should be 190 miles per hour (310km/h) instead of 201 miles per hour (323km/h).[57]
On April 9, 2015, a violent and long-lived tornado struck the communities near Rochelle and in Fairdale, Illinois. The National Weather Service office in Chicago, Illinois, rated the tornado EF4 with winds of at least 200 miles per hour (320km/h), a single mile per hour shy of an EF5 rating. This rating was based on the several structures and an entire farmstead that were completely leveled.[108] Near one of these leveled homes, the tornado moved part of a concrete walkway through the ground. Mechanical engineer Ethan Moriarty conducted an engineering-based analysis on the tornado and stated, the walkway being moved was "the most impressive damage indicator in this path is this one right here". In the analysis, Moriarty determined winds of at least 226 miles per hour (364km/h) were needed to move the sidewalk through the ground.[109] In 2022, Walker Ashley, a PhD meteorology professor at the Northern Illinois University, stated, "there's still some debate, even to this day [between meteorologists] as to whether it should have been categorized as an EF5".[110] On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society, where they stated the tornado in Rochelle was an "EF5 candidate". It was also explained that the EF5 starting wind speed should be 190 miles per hour (310km/h) instead of 201 miles per hour (323km/h).[57]
A wooden-cabin swept clean off of their foundation near Cantwell Mill at high-end EF4 intensity
On April 12, 2020, an enormous and deadly tornado struck the southeastern parts of Bassfield and directly struck the communities of Soso, Moss, and Pachuta, Mississippi, as well as rural areas near Seminary and Heidelberg, Mississippi. The National Weather Service office in Jackson, Mississippi rated the tornado EF4 with winds of at least 190 miles per hour (310km/h), based on a well-anchored wooden cabin that was obliterated and swept clean, with the metal roof being completely stripped away. Despite how well-built the home was, high-end EF4 rating was kept due to minor structural issues along with the suspicion a truck slammed into the home, compromising the structure.[113][114][77]
On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society, where they stated the tornado in Bassfield was an "EF5 candidate". It was also explained that the EF5 starting wind speed should be 190 miles per hour (310km/h) instead of 201 miles per hour (323km/h).[57]
2020 Scarth tornado
On August 7, 2020, a photogenic tornado struck in southern Manitoba, passing near the towns of Virden and Scarth. Damage by the tornado was rated (C)EF3[a] by the Northern Tornadoes Project on August 8.[115][116][117][118]
On August 1, 2024, four professors at the University of Western Ontario and employees of the Northern Tornadoes Project, published a paper through the American Meteorological Society where they analyzed two vehicles thrown by the tornado.[119] The researchers determined that the vehicles have to have been picked up at least 1 metre (1.1yd) vertically in the air and they were thrown 30 to 100 metres (33 to 109yd) horizontally once picked up. This would have required the tornado to have had winds of at least 110m/s (250mph), which the researchers noted was well above the criteria for an EF5 tornado. 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".[119]
On June 24, 2021, a rare, violent, and deadly long-tracked tornado struck several villages in the Hodonín and Břeclav districts of the South Moravian Region of the Czech Republic. The European Severe Storms Laboratory, along with the Czech Hydrometeorological Institute (CHMI), Slovak Hydrometeorological Institute (SHMÚ), and Charles University, rated the worst of the damage IF4 on the new International Fujita scale. In Moravská Nová Ves and Mikulčice, hundreds of buildings were severely damaged or destroyed, including a few well-built brick and masonry homes that were completely leveled. The concrete exterior walls of structures that remained standing were scarred and impaled by flying projectiles. A few trees were completely stripped clean of all bark. In the towns, three locations sustained IF4 damage. The first location was a row of newly built homes. "Here, an IF4 rating was assigned to the damage of three well-built brick structures. One of the brick structures was completely destroyed, which would warrant an IF5 rating. However, a rather weak connection between the roof and the walls was found, which prevented the damage from being assigned an IF5 rating. Another structure that was completely destroyed was still under construction. Debris from the houses were carried over the following field along considerable distances."[120] In all, a total of 1,200 buildings were damaged or destroyed by the IF4 tornado, which had an estimated peak windspeed of 380km/h (236.1mph) and 14 different locations sustained IF4 level damage.[121][122][123]
The highest-rated damage from the tornado; a house completely leveled in BremenRadar 3D volume scan of the supercell showing debris lofted over 30,000 feet (9.1km) in the air as the tornado struck Mayfield
In 2022, Timothy Marshall, a meteorologist, structural and forensic engineer; Zachary B. Wienhoff, with 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 tornado's track, particularly through Mayfield and Dawson Springs. The report notes: "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."[126] 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.[127] 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".[127]
On April 29, 2022, a well documented tornado struck the city of Andover, Kansas. On May 2, the National Weather Service office in Wichita, Kansas rated the tornado EF3 with winds of at least 165 miles per hour (266km/h).[128] However, this was later decreased to 155 miles per hour (249km/h).[129] On October 26, 2022, at the American Meteorological Society's 30th Conference on Severe Local Storms, the European Severe Storms Laboratory (ESSL) presented evidence through photogrammetry using a drone video taken by Reed Timmer. In the presentation, ESSL showed that the tornado had winds of at least 118.0 metres per second (264mph) and a graphic showing the tornado was approximately IF4 to IF5 intensity on the International Fujita scale.[130][bettersourceneeded]
High-end EF4 damage to The Green Apple Florist in Rolling Fork
On March 24, 2023, a large and multi-vortex wedge tornado struck the city of Rolling Fork and the town of Silver City, Mississippi. On March 27, the National Weather Service (NWS) office in Jackson, Mississippi, along with the help of the National Severe Storms Laboratory (NSSL) and the PERiLS Project, rated the tornado EF4 with winds of 170 miles per hour (270km/h).[131] On June 6, the National Weather Service upgraded the tornado to EF4 with winds of 195 miles per hour (314km/h), following "consultation from tornado damage and structural engineering experts" and additional surveys conducted by the NSSL, University of Oklahoma, the NIST, and Haag Engineering.[132]
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 it was rated EF4 rather than EF5.[133] 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[133]
On January 23, 2025, Anthony W. Lyza with the National Severe Storms Laboratory along with Harold E. Brooks and Makenzie J. Kroca with the University of Oklahoma’s School of Meteorology published a paper to the American Meteorological Society, where they stated the Rolling Fork tornado was an "EF5 candidate" at the floral shop. It was also explained that the EF5 starting wind speed should be 190 miles per hour (310km/h) instead of 201 miles per hour (323km/h).[57]
2023 Matador tornado
On June 21, 2023, an intense tornado struck the town of Matador, Texas. On June 24, the National Weather Service office in Lubbock, Texas, with "consultation with engineers from the Texas Tech University National Wind Institute", rated the tornado EF3 with winds of at least 165 miles per hour (266km/h).[134]
Following the tornado, several meteorologists and storm chasers questioned the tornado's EF3 rating saying it was "a gross underestimate of such a violent tornado", as it completely leveled and swept away multiple structures and produced extreme contextual damage to vehicles and vegetation.[135][136]Mechanical engineer Ethan Moriarty stated with regards to the extreme vehicle damage that "the problem is that we can't really go outside of the confines of the scale"..."that's the thing with standards like this. You have to stay consistent, even if they are limiting the actual classification of the tornado". One issue with the Enhanced Fujita scale stated by Moriarty is that vehicles are not a specific damage indicator on the scale, meaning they cannot be used to rate the tornado.[137] In addition, the tornado was slow moving, which may have exacerbated the severity of the damage. Chief meteorologist for KWTV-DTDavid Payne stated the damage in Matador, "looks like EF4 damage to me".[138][139]
2023 Didsbury tornado
On July 1, 2023, a violent (C)EF4 tornado,[a] struck the rural Mountain View County in Alberta, Canada, causing damage particularly between the towns of Didsbury and Carstairs. On July 4, the Environment and Climate Change Canada (ECCC), the Prairie and Arctic Storm Prediction Centre (PASPC), and the Northern Tornadoes Project (NTP) published a joint-damage survey, rating the tornado low-end EF4 with winds of 275 kilometres per hour (171mph). This rating was based on major damage at a farmstead, where a well-built house was completely leveled with debris scattered across nearby fields. A large 22,000-pound (10,000kg) combine near this home was thrown 50m (160ft) before being rolled a further 50 to 100m (160 to 330ft), however, the combine was unable to be used in the rating of the tornado.[140]
On August 1, 2024, four professors at the University of Western Ontario and employees of the Northern Tornadoes Project, published a paper through the American Meteorological Society where they determined the combine harvester was likely lofted roughly 1.26m (1.38yd) into the air, with median estimated winds of 118m/s (260mph) being needed to lift and thrown the combine. 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".[119]
A DOW image of the Greenfield tornado as it approached the southwestern edge of GreenfieldAerial imagery of EF4 damage to homes in northeastern Greenfield, Iowa. Peak wind speeds were estimated at 170mph (270km/h) here
On May 21, 2024, a violent and destructive tornado struck the communities of Villisca, Nodaway, Brooks, Corning, and Greenfield in southwestern Iowa. On May 23, the National Weather Service office in Des Moines, Iowa, rated the tornado EF4 with estimated winds between 175–185 miles per hour (282–298km/h).[141] This was later revised up to 185 miles per hour (298km/h).[142]
On the day of the tornado, the Doppler on Wheels (DOW) team made a very preliminary analysis, suggesting a Doppler on Wheels measured winds of at least 90m/s (200mph).[143] The next day, a further preliminary analysis by the DOW team determined that a Doppler on Wheels measured winds of at least >250mph (400km/h), "possibly as high as 290mph (470km/h)" at 48 yards (44m) above the surface, as the tornado moved through the town. Pieter Groenemeijer, the director of the European Severe Storms Laboratory noted that "on the IF-scale, 250 mph measured below 60 m above ground level is IF4 on the IF-scale, 290 mph is IF5."[144]
On June 24, after further analysis, the report was revised to winds of 308–319mph (496–513km/h) in a brief 1 second gust, based on the measurement of 263–271mph (423–436km/h) at 36–38 yards (33–35m) above the surface.[145][146] This preliminary data suggests that the Greenfield, Iowa EF4 tornado had the third highest measured wind speeds recorded in a tornado and was the third tornado to ever been recorded to be over 300mph.
Across the street from the Adair County Memorial Hospital, the tornado ripped new concrete parking lot stop blocks from the ground, which were installed sometime after August 2023. Mechanical engineer Ethan Moriarty calculated that winds of at least 247 miles per hour (398km/h) was needed to rip the concrete stop blocks out of the ground if they were cracked prior to being pulled up, or 283 miles per hour (455km/h) if they were uncracked prior to being ripped out of the ground. The tornado, once nearly a mile wide at one point, had reduced in size significantly before impacting Greenfield, with the conservation of angular momentum potentially being responsible for the tornado's intensity near the end of its life. In the conclusion of his analysis, Moriarty stated that he believed the tornado was "without question a tornado capable of EF5 damage", while stating that, had the tornado been rated on a scale other than the Enhanced Fujita scale, it may have received a higher rating.[147]
1 2 Canada uses a different version of the Enhanced Fujita scale, which is still commonly called the "EF-scale". The Canadian version of the scale is officially known as the "Canadian Enhanced Fujita scale" or "CEF-scale".
1 2 3 4 5 6 Grazulis, Thomas P (July 1993). Significant Tornadoes 1680-1991. St. Johnsbury, VT: The Tornado Project of Environmental Films. ISBN1-879362-03-1.
↑ Fujita, Tetsuya Theodore (August 1970). "The Lubbock Tornadoes: A Study of Suction Spots". Weatherwise. 23 (4). Routledge: 161–173. doi:10.1080/00431672.1970.9932888.
↑ National Centers for Environmental Information. "Texas Event Report: F4 Tornado". Storm Event Database. National Oceanic and Atmospheric Administration. Archived from the original on 22 May 2023. Retrieved 22 May 2023.
↑ Jim LaDue; Tim Marshall; Kevin Scharfenberg (2012). "Discriminating EF4 and EF5 Tornado Damage"(PDF). National Weather Service Office in Norman, Oklahoma. National Oceanic and Atmospheric Administration. Retrieved June 26, 2013.
↑ Prevatt, David O.; Roueche, David B.; van de Lindt, John W.; Pei, Shiling; Dao, Thang; Coulbourne, William; Graettinger, Andrew J.; Gupta, Rakesh; Grau, David (March 29, 2012). "Building Damage Observations and EF Classifications from the Tuscaloosa, AL, and Joplin, MO, Tornadoes". Structures Congress 2012. pp.999–1010. doi:10.1061/9780784412367.089. ISBN9780784412367.
1 2 3 4 Ortega, Kiel L.; Bluestein, Howard B.; Burgess, Donald W.; etal. (January 25, 2012). Overview of the May 24 2011 Tornado Outbreak. 92nd American Meteorological Society Annual Meeting, Special Symposium on the Tornado Disasters of 2011. Archived from the original on February 7, 2023. Retrieved February 10, 2023– via American Meteorological Society.
↑ "March 2, 2012 Tornado Outbreak". National Weather Service office in Louisville, Kentucky. National Oceanic and Atmospheric Administration. March 6, 2012. Retrieved March 7, 2012.
↑ "Mississippi Event Report: EF2 Tornado" (Report). National Centers for Environmental Information. National Weather Service Weather Forecast Office in Memphis, Tennessee. 2019. Retrieved July 18, 2019.
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