A tornado damage survey, also known as a storm damage assessment, is a type of land survey that is conducted to determine the damage caused by tornadoes, and to give them ratings on the Enhanced Fujita scale. Damage surveys have been used since the 18th century to determine tornado-caused damage, and have become increasingly common following the implementation of the Fujita scale in 1971.
Although it is unknown when damage surveys began to be used to determine structural and property damage, one of the earliest known surveys was conducted by German scientist Gottlob Burchard Genzmer in the aftermath of the 1764 Woldegk tornado. Genzmer published a detailed survey of the damage path from the tornado, which documented the 33 km (18.6 mi) long track. The study, known as the "Genzmer Report", was the first to be conducted on a single tornado. [1]
Damage surveys would become more common in the 1960s and 1970s, when Ted Fujita pioneered the Fujita scale, [2] used to determine the strength of tornadoes. Fujita himself had surveyed damage after the atomic bombing of Nagasaki to determine where the bomb had exploded from. [3] Following the Fargo tornado in 1957, Fujita conducted one of the first damage surveys using photographic evidence and ground measurements, using 200 photos to determine the approximate track of the tornado. [4] Following the implementation of the Fujita Scale in 1971, [5] hundreds of post-event damage surveys have been conducted on tornadoes and other weather events to determine the rating of the tornado. [6] In the 2020s, drones have been used to survey hard-to-access areas, most notably following the 2021 Western Kentucky tornado. [7]
Since 2009, the Damage Assessment Toolkit (DAT), used by the National Weather Service, has been used to publish the preliminary results of damage surveys. An estimated 38,000 individual damage points have been recorded using the software. [8]
The Fujita scale, or Fujita–Pearson 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 a ground or aerial damage survey, or both; and depending on the circumstances, ground-swirl patterns, 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 the EF-Scale over the Fujita scale along with 31 "Specific Damage Indicators" used by Environment Canada (EC) in their ratings.
This article lists various tornado records. The most "extreme" tornado in recorded history was the Tri-State tornado, which spread through parts of Missouri, Illinois, and Indiana on March 18, 1925. It is considered an F5 on the Fujita Scale, holds records for longest path length at 219 miles (352 km) and longest duration at about 3+1⁄2 hours. The 1974 Guin tornado had the highest forward speed ever recorded in a violent tornado, at 75 mph (121 km/h). The deadliest tornado in world history was the Daulatpur–Saturia tornado in Bangladesh on April 26, 1989, which killed approximately 1,300 people. In the history of Bangladesh, at least 19 tornadoes killed more than 100 people each, almost half of the total for the world. The most extensive tornado outbreak on record was the 2011 Super Outbreak, which resulted in 367 tornadoes and 324 tornadic fatalities, whereas the 1974 Super Outbreak was the most intense tornado outbreak on tornado expert Thomas P. Grazulis's outbreak intensity score with 578, as opposed to the 2011 outbreak's 378.
The National Severe Storms Laboratory (NSSL) is a National Oceanic and Atmospheric Administration (NOAA) weather research laboratory under the Office of Oceanic and Atmospheric Research. It is one of seven NOAA Research Laboratories (RLs).
A destructive tornado outbreak impacted the Midwestern United States and Tennessee River Valley on November 15, 2005. It occurred along a cold front separating warm, humid air from the southeast from cold Arctic air to the north and northwest. 49 tornadoes were confirmed in the central United States in the states of Alabama, Arkansas, Illinois, Indiana, Kentucky, Missouri and Tennessee over that afternoon and evening. Strong winds and large hail caused additional damage throughout the region.
The Enhanced Fujita scale rates tornado intensity based on the severity of the damage they cause. It is used in some countries, including the United States and France. The EF scale is also unofficially used in other countries, including China and Brazil. The rating of a tornado is determined by conducting a tornado damage survey.
This page documents the tornadoes and tornado outbreaks that occurred in 2007, primarily in the United States. Most tornadoes form in the U.S., although some events may take place internationally, particularly in parts of neighboring southern Canada during the summer season. Some tornadoes also take place in Europe, e. g. in the United Kingdom or in Germany.
Tornado intensity is the measure of wind speeds and potential risk produced by a tornado. Intensity can be measured by in situ or remote sensing measurements, but since these are impractical for wide-scale use, intensity is usually inferred by proxies, such as damage. The Fujita scale, Enhanced Fujita scale, and the International Fujita scale rate tornadoes by the damage caused. In contrast to other major storms such as hurricanes and typhoons, such classifications are only assigned retroactively. Wind speed alone is not enough to determine the intensity of a tornado. An EF0 tornado may damage trees and peel some shingles off roofs, while an EF5 tornado can rip well-anchored homes off their foundations, leaving them bare— even deforming large skyscrapers. The similar TORRO scale ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes. Doppler radar data, photogrammetry, and ground swirl patterns may also be analyzed to determine the intensity and assign a rating.
A violent severe weather outbreak struck the Southeast on April 4–5, 1977. A total of 22 tornadoes touched down with the strongest ones occurring in Mississippi, Alabama, and Georgia. The strongest was a catastrophic F5 tornado that struck the northern Birmingham, Alabama, suburbs during the afternoon of Monday, April 4. In addition to this tornado, several other tornadoes were reported from the same system in the Midwest, Alabama, Georgia, Mississippi and North Carolina. One tornado in Floyd County, Georgia, killed one person, and another fatality was reported east of Birmingham in St. Clair County. In the end, the entire outbreak directly caused 24 deaths and 158 injuries. The storm system also caused the crash of Southern Airways Flight 242, which killed 72 and injured 22.
This page documents the tornadoes and tornado outbreaks of 2014. Strong and destructive tornadoes form most frequently in the United States, Bangladesh, Brazil, and Eastern India, but they can occur almost anywhere under the right conditions. Tornadoes also appear regularly in neighboring southern Canada during the Northern Hemisphere's summer season, and somewhat regularly in Europe, Asia, and Australia.
The following is a glossary of tornado terms. It includes scientific as well as selected informal terminology.
Storm Data and Unusual Weather Phenomena (SD) is a monthly NOAA publication with comprehensive listings and detailed summaries of severe weather occurrences in the United States. Included is information on tornadoes, high wind events, hail, lightning, floods and flash floods, tropical cyclones (hurricanes), ice storms, snow, extreme temperatures such as heat waves and cold waves, droughts, and wildfires. Photographs of weather and attendant damage are used as much as possible. Maps of significant weather are also included.
This page documents notable tornadoes and tornado outbreaks worldwide in 2018. Strong and destructive tornadoes form most frequently in the United States, Brazil, Bangladesh and Eastern India, but they can occur almost anywhere under the right conditions. Tornadoes also develop occasionally in southern Canada during the Northern Hemisphere's summer and somewhat regularly at other times of the year across Europe, Asia, Argentina and Australia. Tornadic events are often accompanied with other forms of severe weather, including strong thunderstorms, strong winds, and hail. There were 1,169 preliminary filtered reported tornadoes and 1,121 confirmed tornadoes in the United States in 2018. Worldwide, 17 tornado-related deaths were confirmed; 10 in the United States, four in Brazil, two in Indonesia, and one in Canada.
This is a timeline of scientific and technological advancements as well as notable academic or government publications in the area of atmospheric sciences and meteorology during the 21st century. Some historical weather events are included that mark time periods where advancements were made, or even that sparked policy change.
The history of tornado research spans back centuries, with the earliest documented tornado occurring in 200 and academic studies on them starting in the 18th century. This is a timeline of government or academic research into tornadoes.
Between December 28–29, 2024, a late season tornado outbreak affected the Deep South. Multiple tornadoes caused severe damage in the Greater Houston area and in Port Arthur, Texas while additional tornadoes caused damage in other states, including Louisiana, Mississippi, and Alabama. Overall, at least four people have been killed; one in the Houston area, two in Mississippi and one in North Carolina, and 17 more have been injured, two indirectly. In total, 106 tornado warnings were issued during the outbreak.