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 kilometers per hour, are about 80 meters across, and travel several kilometers before dissipating. The most extreme tornadoes can attain wind speeds of more than 480 kilometers per hour (300 mph), can be more than 3 kilometers (2 mi) in diameter, and can stay on the ground for more than 100 km (62 mi).
A storm is any disturbed state of the natural environment or the atmosphere of an astronomical body. It may be marked by significant disruptions to normal conditions such as strong wind, tornadoes, hail, thunder and lightning, heavy precipitation, heavy freezing rain, strong winds, wind transporting some substance through the atmosphere such as in a dust storm, among other forms of severe weather.
Twister is a 1996 American disaster film directed by Jan de Bont, and written by Michael Crichton and Anne-Marie Martin. It was produced by Crichton, Kathleen Kennedy, and Ian Bryce, with Steven Spielberg, Walter Parkes, Laurie MacDonald, and Gerald R. Molen serving as executive producers. The film stars an ensemble cast that includes Helen Hunt, Bill Paxton, Jami Gertz, and Cary Elwes. It follows a group of storm chasers trying to deploy a tornado research device during a severe outbreak in Oklahoma.
Storm chasing is broadly defined as the deliberate pursuit of any severe weather phenomenon, regardless of motive, but most commonly for curiosity, adventure, scientific investigation, or for news or media coverage. A person who chases storms is known as a storm chaser or simply a chaser.
A storm shelter or storm cellar is a type of underground bunker designed to protect the occupants from severe weather, particularly tornadoes. They are most frequently seen in the Midwest and Southeastern United States where tornadoes are generally frequent and the low water table permits underground livings.
Tornado myths are incorrect beliefs about tornadoes, which can be attributed to many factors, including stories and news reports told by people unfamiliar with tornadoes, sensationalism by news media, and the presentation of incorrect information in popular entertainment. Common myths cover various aspects of the tornado, and include ideas about tornado safety, the minimization of tornado damage, and false assumptions about the size, shape, power, and path of the tornado itself.
The TOtable Tornado Observatory is a large, instrumented barrel-shaped device invented in 1979 by engineers Dr. Al Bedard and Carl Ramzy of the National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory (ETL), and Dr. Howard Bluestein, meteorologist at the University of Oklahoma (OU). NOAA's objective was to place the TOTO directly in the path of a tornado, where it could, theoretically, record valuable information about the tornado's structure. The device's nickname, TOTO, originates from Toto the dog in Metro-Goldwyn-Mayer's 1939 film The Wizard of Oz, in which a tornado is a key plot element.
An intense tornado outbreak occurred on May 22 in western and Central Oklahoma and on May 23 from eastern and central Oklahoma to central Iowa. A total of 43 tornadoes were confirmed during the two-day outbreak, of which 14 were recorded as strong or violent. The outbreak resulted in no fatalities and only 12 injuries from a tornado that touched down near Clinton, Oklahoma, which caused significant damage. The tornado outbreak overall left $32.8 million in damage.
Tornadoes have been recorded on all continents except Antarctica. They are most common in the middle latitudes where conditions are often favorable for convective storm development. The United States has the most tornadoes of any country, as well as the strongest and most violent tornadoes. A large portion of these tornadoes form in an area of the central United States popularly known as Tornado Alley. Canada experiences the second most tornadoes. Ontario and the prairie provinces see the highest frequency. Other areas of the world that have frequent tornadoes include significant portions of Europe, South Africa, Philippines, Bangladesh, parts of Argentina, Uruguay, and southern and southeastern Brazil, northern Mexico, eastern and western Australia, New Zealand, and far eastern Asia.
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.
The Tornado Intercept Vehicle 1 and Tornado Intercept Vehicle 2 are vehicles used to film with an IMAX camera from very close to or within a tornado. They were designed by film director Sean Casey. Both TIVs have "intercepted" numerous tornadoes, including the June 12, 2005, Jayton, Texas tornado, the June 5, 2009, Goshen County, Wyoming tornado, and the strongest intercept, made by TIV 2, the May 27, 2013, Lebanon, Kansas tornado.
The effects of tropical cyclones include heavy rain, strong wind, large storm surges near landfall, and tornadoes. The destruction from a tropical cyclone, such as a hurricane or tropical storm, depends mainly on its intensity, its size, and its location. Tropical cyclones remove forest canopy as well as change the landscape near coastal areas, by moving and reshaping sand dunes and causing extensive erosion along the coast. Even well inland, heavy rainfall can lead to landslides in mountainous areas. Their effects can be sensed over time by studying the concentration of the Oxygen-18 isotope within caves.
Night of the Twisters is a 1996 made-for-television disaster film that was directed by Timothy Bond. The film premiered on The Family Channel on February 11, 1996, as the cable channel's first original movie.
A tornado emergency is an enhanced version of a tornado warning, which is used by the National Weather Service (NWS) in the United States during imminent, significant tornado occurrences in highly populated areas. Although it is not a new warning type from the NWS, issued instead within a severe weather statement or in the initial tornado warning, a tornado emergency generally means that significant, widespread damage is expected to occur and a high likelihood of numerous fatalities is expected with a large, strong to violent tornado.
The 2007 Brooklyn tornado was the strongest tornado on record to strike in New York City. It formed in the early morning hours of August 8, 2007, skipping along an approximately 9 miles (14 km)-long path, from Staten Island across The Narrows to Brooklyn. The worst damage was in and around Sunset Park and Bay Ridge, in Brooklyn. The U.S. National Weather Service estimated its strength there as an EF2 on the Enhanced Fujita scale.
Tornadoes are more common in the United States than in any other country or state. The United States receives more than 1,200 tornadoes annually—four times the amount seen in Europe. Violent tornadoes—those rated EF4 or EF5 on the Enhanced Fujita Scale—occur more often in the United States than in any other country.
The 1999 Bridge Creek–Moore tornado was a large, long-lived and exceptionally powerful F5 tornado in which the highest wind speed ever measured globally was recorded at 321 miles per hour (517 km/h) by a Doppler on Wheels (DOW) radar. Considered the strongest tornado ever recorded to have affected the Oklahoma City metropolitan area, the tornado devastated southern portions of Oklahoma City, Oklahoma, United States while near peak intensity, along with surrounding suburbs and towns to the south and southwest of the city during the early evening of Monday, May 3, 1999. Parts of Bridge Creek were rendered unrecognizable. The tornado covered 38 miles (61 km) during its 85-minute existence, destroying thousands of homes, killing 36 people, and leaving US$1 billion in damage, ranking it as the fifth-costliest on record not accounting for inflation. Its severity prompted the first-ever use of the tornado emergency statement by the National Weather Service.
The term "tornado preparedness" refers to safety precautions made before the arrival of and during a tornado. Historically, the steps taken have varied greatly, depending on location, or time remaining before a tornado was expected. For example, in rural areas, people might prepare to enter an external storm cellar, in case the main building collapses, and thereby allow exit without needing rescue from the main building as in urban areas. Because tropical storms have spawned many tornadoes, hurricane preparations also involve tornadoes. The term "tornado preparedness" has been used by government agencies, emergency response groups, schools, insurance companies, and others.
The 2013 El Reno tornado was an extremely large, powerful, and erratic tornado that occurred over rural areas of Central Oklahoma during the early evening of Friday, May 31, 2013. This rain-wrapped, multiple-vortex tornado was the widest tornado ever recorded and was part of a larger weather system that produced dozens of tornadoes over the preceding days. The tornado initially touched down at 6:03 p.m. Central Daylight Time (2303 UTC) about 8.3 miles (13.4 km) west-southwest of El Reno, rapidly growing in size and becoming more violent as it tracked through central portions of Canadian County. Remaining over mostly open terrain, the tornado did not impact many structures; however, measurements from mobile weather radars revealed extreme winds in excess of 313 mph (504 km/h) within the vortex. These are among the highest observed wind speeds on Earth, just slightly lower than the wind speeds of the 1999 Bridge Creek–Moore tornado. As it crossed U.S. 81, it had grown to a record-breaking width of 2.6 miles (4.2 km), beating the previous width record set in 2004. Turning northeastward, the tornado soon weakened. Upon crossing Interstate 40, the tornado dissipated around 6:43 p.m. CDT (2343 UTC), after tracking for 16.2 miles (26.1 km), it avoided affecting the more densely populated areas near and within the Oklahoma City metropolitan area.
The following is a glossary of tornado terms. It includes scientific as well as selected informal terminology.
