A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the word cyclone is used in meteorology to name a weather system with a low-pressure area in the center around which, from an observer looking down toward the surface of the Earth, winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern. Tornadoes come in many shapes and sizes, and they are often visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it. Most tornadoes have wind speeds less than 180 km/h (110 mph), are about 80 m across, and travel several kilometers before dissipating. The most extreme tornadoes can attain wind speeds of more than 480 km/h (300 mph), are more than 3 km in diameter, and stay on the ground for more than 100 km.
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, even though tornadoes were not ranked on any scale at the time. It holds records for longest path length at 219 miles (352 km), longest duration at about 3½ hours, and fastest forward speed for a significant tornado at 73 mph (117 km/h) anywhere on Earth. In addition, it is the deadliest single tornado in United States history with 695 fatalities. It was also the third most costly tornado in history at the time, but has been surpassed by several others non-normalized. When costs are normalized for wealth and inflation, it still ranks third today.
The 2005 Birmingham tornado was one of the strongest tornadoes recorded in Great Britain in nearly 30 years, occurring on 28 July 2005 in the suburbs of Birmingham. It formed on a day when thunderstorms were expected to develop across the Midlands and eastern England. The tornado struck at approximately 14:30 BST in the Sparkbrook area and also affected King's Heath, Moseley and Balsall Heath as it carved a 7 kilometre-long path through the city.
The TORRO tornado intensity scale is a scale measuring tornado intensity between T0 and T11. It was proposed by Terence Meaden of the Tornado and Storm Research Organisation (TORRO), a meteorological organisation in the United Kingdom, as an extension of the Beaufort scale.
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, Canada, China, and Mongolia.
The Grand Harbour of Malta tornado was a tornado that hit the Grand Harbour of Malta with very intense strength. It began as a waterspout killing at least 600 people. At least four of the Order's galleys, named Santa Fè, San Michele, San Filippo and San Claudio, capsized in the tornado. The date of the tornado is unknown, as sources conflict on it being September 23, 1551 or September 23, 1556. TORRO indicates a rating of T7 on the TORRO scale, equivalent to F3 on the Fujita scale.
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. The Enhanced Fujita scale was an upgrade to the older Fujita scale, with engineered wind estimates and better damage descriptions, but was designed so that a tornado rated on the Fujita scale would receive the same numerical rating. 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 will probably damage trees and peel some shingles off the roof. An EF5 tornado can rip well-anchored homes off their foundations, leaving them bare, and can even deform 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.
The 2006 London tornado was a significant United Kingdom tornado spawned from a squall line moving over the city on 7 December 2006 at approximately 11:02 GMT. Its intensity is estimated to have been T4 on the TORRO scale, equating to F2 on the Fujita scale.
Severe weather is any dangerous meteorological phenomenon with the potential to cause damage, serious social disruption, or loss of human life. Types of severe weather phenomena vary, depending on the latitude, altitude, topography, and atmospheric conditions. High winds, hail, excessive precipitation, and wildfires are forms and effects of severe weather, as are thunderstorms, downbursts, tornadoes, waterspouts, tropical cyclones, and extratropical cyclones. Regional and seasonal severe weather phenomena include blizzards (snowstorms), ice storms, and duststorms. Extreme weather phenomena which cause extreme heat, cold, wetness or drought often will bring severe weather events. One of the principal effects of anthropogenic climate change is changes in severe and extreme weather patterns.
The London Tornado of 1091 is the earliest reported tornado in England, occurring in London on Friday, 17 October 1091. It has been reckoned by modern assessment as possibly a T8 on the TORRO scale making it potentially the strongest recorded tornado in the British Isles, although this estimate is based on reports written 30 years after the tornado. The church of St Mary-le-Bow in the city of London was badly damaged; four rafters 26 feet (7.9 m) long were driven into the ground so that only 4 feet (1.2 m) protruded above the surface. Other churches in the area were demolished, as were over 600 houses. For all the damage inflicted, the tornado claimed just two known victims from a population of about 18,000. The tornado is mentioned in chronicles by Florence of Worcester and William of Malmesbury, the latter describing it as "a great spectacle for those watching from afar, but a terrifying experience for those standing near".
Europe is generally characterized by a temperate climate. Most of Western Europe has an Oceanic climate, in the Köppen climate classification, featuring cool to warm summers and cool winters with frequent overcast skies. Southern Europe has a distinctively Mediterranean climate, which features warm to hot, dry summers and cool to mild winters and frequent sunny skies. Central-eastern Europe is classified as having a humid continental climate, which features warm to hot summers and cold winters.
This page documents the tornadoes and tornado outbreaks of 1981, primarily in the United States. Most tornadoes form in the U.S., although some events may take place internationally. Tornado statistics for older years like this often appear significantly lower than modern years due to fewer reports or confirmed tornadoes.
The International Fujita scale rates the intensity of tornadoes and other wind events based on the severity of the damage they cause. It is used by the European Severe Storms Laboratory (ESSL) and is being worked on by various other organizations including Deutscher Wetterdienst (DWD) and State Meteorological Agency (AEMET). The scale is intended to be analogous to the Fujita and Enhanced Fujita scales, while being more applicable internationally by accounting for factors such as differences in building codes.
This page documents the tornadoes and tornado outbreaks of 1948, primarily in the United States. Most tornadoes form in the U.S., although some events may take place internationally. Tornado statistics for older years like this often appear significantly lower than modern years due to fewer reports or confirmed tornadoes. Also, prior to 1950, tornadoes were not officially surveyed by the U.S. Weather Bureau, which would later become the National Weather Service, and thus had no official rating. All documented significant tornadoes were instead given unofficial ratings by tornado experts like Thomas P. Grazulis.