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33-415: (Redirected from F-Scale ) F scale may refer to: F-scale (personality test) , a personality test that attempts to quantify authoritarian tendencies Fujita scale , a system of rating of a tornado's intensity by its impact on structures and vegetation F scale (modelling) , a 1:20.3 scaled gauge track used with model trains F Scale, a validity scale of

66-508: A storm chaser noting that despite his fascination with storms he had never actually seen a tornado. He saw his first tornado, a very large one, near Tulsa, Oklahoma on Memorial Day of that year. By the late 1990s, Grazulis also constructed a variety of designs of physical simulator models of vortices . He used these for air flow experiments and for displays. Grazulis had long been interested in tornado simulators and included earlier laboratory studies in his TVC documentaries. The Secrets of

99-656: A fatality) in the U.S. back to 1880. The Fujita scale was adopted in most areas outside of the United Kingdom . On February 1, 2007, the Fujita scale was decommissioned, and the Enhanced Fujita Scale was introduced in the United States. The new scale more accurately matches wind speeds to the severity of damage caused by the tornado. Though each damage level is associated with a wind speed,

132-619: A ground or aerial damage survey , or both; and depending on the circumstances, ground-swirl patterns ( cycloidal marks), weather radar data, witness testimonies, media reports and damage imagery, as well as photogrammetry or videogrammetry if motion picture recording is available. The Fujita scale was replaced with the Enhanced Fujita scale (EF-Scale) in the United States in February 2007. In April 2013, Canada adopted

165-403: A means to differentiate tornado intensity and path area, assigned wind speeds to damage that were, at best, educated guesses. Fujita and others recognized this immediately and intensive engineering analysis was conducted through the rest of the 1970s. This research, as well as subsequent research, showed that tornado wind speeds required to inflict the described damage were actually much lower than

198-502: A tornado rated F4 based on damage with a path length of 63 miles (101 km) and a path width of 800 yards (730 m) would be rated F,P,P 4,4,4. Use of the Pearson scales was not widespread, however, and it remained more common to simply list a tornado's path length and path width directly. For purposes such as tornado climatology studies, Fujita scale ratings may be grouped into classes. The Fujita scale, introduced in 1971 as

231-772: Is a Fellow of the American Meteorological Society (AMS) and was on the Fujita Scale Forum of the Fujita Scale Enhancement Project; which developed the Enhanced Fujita scale to supplant the original Fujita scale . Grazulis initially produced documentaries on the Earth sciences before focusing on tornadoes and publishing books. He expanded to direct-to-video documentaries (which include extensive printed guides) and posters (with complementary background sheets) in

264-453: Is different from Wikidata All article disambiguation pages All disambiguation pages Fujita scale The Fujita scale ( F-Scale ; / f u ˈ dʒ iː t ə / ), or Fujita–Pearson scale ( FPP scale ), is a scale for rating tornado intensity , based primarily on the damage tornadoes inflict on human-built structures and vegetation. The official Fujita scale category is determined by meteorologists and engineers after

297-707: The Minnesota Multiphasic Personality Inventory the F major scale . See also [ edit ] F-number (disambiguation) F-ratio (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title F scale . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=F_scale&oldid=922252918 " Category : Disambiguation pages Hidden categories: Short description

330-626: The National Science Foundation (NSF). He and his wife Doris, also a teacher and a small business operator, then moved to the St. Johnsbury, Vermont area in 1970. In 1972, they released Approaching the Unapproachable , a documentary film on tornadoes that was the first to consider tornadoes in a scientific context rather than as a hazard and was the first compilation of tornado footage. In 1979, Grazulis began working with

363-850: The Nuclear Regulatory Commission (NRC) to create a history of tornadoes. Specifically, he refined and augmented the databases of tornadoes maintained by the National Severe Storms Forecast Center (NSSFC) in Kansas City, Missouri , as well as the database headed by Ted Fujita at the University of Chicago , with whom he collaborated in developing their respective databases. The objective was to determine tornado occurrence and intensity distributions, i.e. tornado climatology , for risk assessment studies. Grazulis' tornado database work

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396-459: The 1990s. Grazulis also wrote for Storm Track magazine, occasionally for Weatherwise magazine and others, and presents at meteorological and storm chaser conferences. The following is a list of his major works: Grazulis in 2001 penned a book for a general readership, an homage and unofficial update to Snowden D. Flora 's classic Tornadoes of the United States (1953), entitled The Tornado: Nature's Ultimate Windstorm . Both were published by

429-620: The EF scale wind speeds, but these are biased to United States construction practices. The EF scale also improved damage parameter descriptions. The original scale as derived by Fujita was a theoretical 13-level scale (F0–F12) designed to smoothly connect the Beaufort scale and the Mach number scale. F1 corresponds to the twelfth level of the Beaufort scale, and F12 corresponds to Mach number 1.0. F0

462-669: The EF-Scale over the Fujita scale along with 31 "Specific Damage Indicators" used by Environment Canada (EC) in their ratings. The scale was introduced in 1971 by Ted Fujita of the University of Chicago , in collaboration with Allen Pearson , head of the National Severe Storms Forecast Center/NSSFC (currently the Storm Prediction Center /SPC). The scale was updated in 1973, taking into account path length and width. In

495-540: The F-scale indicated, particularly for the upper categories. Also, although the scale gave general descriptions of damage a tornado could cause, it gave little leeway for strength of construction and other factors that might cause a building to sustain more damage at lower wind speeds. Fujita tried to address these problems somewhat in 1992 with the Modified Fujita Scale, but by then he was semi-retired and

528-402: The Fujita scale is effectively a damage scale, and the wind speeds associated with the damage listed are not rigorously verified. The Enhanced Fujita Scale was formulated due to research that suggested that the wind speeds required to inflict damage by intense tornadoes on the Fujita scale are greatly overestimated. A process of expert elicitation with top engineers and meteorologists resulted in

561-651: The Grazulis Tornado Project database. As of 2023, the Grazulis database spans from 1680 to 2022 and includes all known significant tornadoes (those rated F2–F5 or causing a fatality). Grazulis' database was digitized and included in an international database combining many resources as they became more available in 2000-2020s, The Tornado Archive. In the early 1990s, he and Doris formed The Tornado Project to market tornado videos, books, and posters. He collaborated with storm chaser Roy Britt to produce

594-719: The National Weather Service was not in a position to update to an entirely new scale, so it went largely unenacted. In the United States, on February 1, 2007, the Fujita scale was decommissioned in favor of what scientists believe is a more accurate Enhanced Fujita Scale. The meteorologists and engineers who designed the EF Scale believe it improves on the F-scale on many counts. It accounts for different degrees of damage that occur with different types of structures, both manmade and natural. The expanded and refined damage indicators and degrees of damage standardize what

627-591: The Tornado documentary featured a detailed instructional segment with an accompanying printed guide for constructing one's own. The Tornado Project's website in 2018 indicated Significant Tornadoes would be updated and released in two volumes of approximately 705 pages each covering tornadoes from 1680 to 1949 and 1950 to 2019. The new volumes will include updates on statistics, graphs, and charts, as well as analysis of trends in tornadic activity and examination of potential influence thereof by climate change . In 2023,

660-511: The U.S. Library of Congress and research libraries but also included local libraries when pertinent. The first book (which was two volumes), resulting from the NRC funded work, was Significant Tornadoes, 1880-1989 . The book filled a gap in tornado information and strong sales led to an expansion, Significant Tornadoes, 1680-1991 . In turn, proceeds of this book and of Tornado Project videos and posters were sufficiently robust to support an update that

693-511: The United States, starting in the late 1970s, tornadoes were rated soon after occurrence. The Fujita scale was applied retroactively to tornadoes reported between 1950 and the adoption of the scale in the National Oceanic and Atmospheric Administration (NOAA) National Tornado Database. Fujita rated tornadoes from 1916 to 1992 and Tom Grazulis of The Tornado Project retroactively rated all known significant tornadoes (F2–F5 or causing

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726-547: The actual wind speeds needed to cause that damage are unknown." Since then, the Enhanced Fujita Scale has been created using better wind estimates by engineers and meteorologists. The six categories are listed here, in order of increasing intensity. In 1973, Allen Pearson added additional path length and path width parameters to the Fujita scale. Under this version, each tornado would be assigned one Fujita scale rating and two Pearson scale ratings. For example,

759-447: The damage described at each category. The error manifests itself to an increasing degree as the category increases, especially in the range of F3 through F5. NOAA notes that "precise wind speed numbers are actually guesses and have never been scientifically verified. Different wind speeds may cause similar-looking damage from place to place—even from building to building. Without a thorough engineering analysis of tornado damage in any event,

792-672: The first volume, Significant Tornadoes: 1974-2022 , was published. Within the book Significant Tornadoes 1974–2022 Grazulis created a new scale called the outbreak intensity score (OIS) to rank tornado outbreaks . For the OIS, only significant tornadoes, those rated F2 to F5 on the Fujita scale and those rated EF2 to EF5 on the Enhanced Fujita scale are used for the score of the outbreak. F2/EF2 tornadoes are given 2 points, F3/EF3 tornadoes are given 5 points, F4/EF4 tornadoes are given 10 points, and F5/EF5 tornadoes are given 15 points. Grazulis

825-507: The popular Tornado Video Classics documentary series. In 1995, they adapted this collection for television to broadcast on The Learning Channel (TLC), and produced less advanced direct-to video documentaries catering to a wider audience, including Twister: Fury on the Plains and Twister: Nature's Fury . His book Significant Tornadoes is considered a critical and authoritative source among severe storms meteorologists. In 1997, he became

858-500: The power of a tornado at age 11 following the violent 1953 Worcester tornado , an F4 which killed 94 people and passed approximately 1 mi (1.6 km) north of his childhood home. Grazulis earned a bachelor's degree in meteorology from Florida State University (FSU) and was briefly a broadcaster, in part presenting the weather. He was a science teacher in New Jersey and worked on the "Earth Science Curriculum Project" with

891-581: The rating of F6, but both were later downgraded to F5. Based on aerial photographs of the damage it caused, Fujita assigned the strongest tornado of the 1974 Super Outbreak , which affected Xenia, Ohio, a preliminary rating of F6 intensity ± 1 scale. The 1977 Birmingham–Smithfield F5 tornado's damage was surveyed by Ted Fujita and he "toyed with the idea of rating the Smithfield tornado an F6". In 2001, tornado expert Thomas P. Grazulis stated in his book F5–F6 Tornadoes ; "In my opinion, if there ever

924-475: Was an F6 tornado caught on video, it was the Pampa, Texas tornado of 1995 ". In 2023, it was announced by the Storm Prediction Center and National Weather Service Norman, Oklahoma that the 1970 Lubbock tornado was originally rated F6, which was later downgraded to its official rating of F5. Furthermore, the original wind speed numbers have since been found to be higher than the actual speeds required to incur

957-553: Was available on damage caused by wind, so the original scale presented little more than educated guesses at wind speed ranges for specific tiers of damage. Fujita intended that only F0–F5 be used in practice, as this covered all possible levels of damage to frame homes as well as the expected estimated bounds of wind speeds. He did, however, add a description for F6, which he called an "inconceivable tornado", to allow for wind speeds exceeding F5 and possible advancements in damage analysis that might show it. In total, two tornadoes received

990-591: Was considered important enough that he was awarded five years of additional funding from the National Science Foundation. In the process, Grazulis traveled the country visiting dozens of libraries, museums, university archives, historical societies, and the like, to eventually chronicle 60,000 tornadoes, 50,000 of them included in a single 1,400-page book that is widely referenced. It is estimated he read 25,000 microfilm reels of (mostly major) newspapers. His work concentrated in state libraries and

1023-410: Was placed at a position specifying no damage (approximately the eighth level of the Beaufort scale), in analogy to how Beaufort's zeroth level specifies little to no wind. From these wind speed numbers, qualitative descriptions of damage were made for each category of the Fujita scale, and then these descriptions were used to classify tornadoes. At the time Fujita derived the scale, little information

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1056-548: Was published for the years 1992–1995. Significant Tornadoes contains 51 photographs of tornadoes prior to 1970, the most extensive collection published. Grazulis amassed one of three authoritative tornado databases, those being the National Tornado Database assembled and maintained by NOAA agencies, the University of Chicago DAPPL database founded by Fujita which ended at his retirement in 1992, and

1089-612: Was somewhat ambiguous. It also is thought to provide much better estimates of wind speeds and sets no upper limit on the wind speeds for the highest level, EF5. Environment Canada began using the Enhanced Fujita scale in Canada on April 1, 2013. The U.S. and Canada are the only countries to officially adopt the Enhanced Fujita scale. Tom Grazulis Thomas Grazulis grew up in Worcester, Massachusetts and first confronted

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