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.
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 epic disaster film directed by Jan de Bont from a screenplay 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, Cary Elwes, Philip Seymour Hoffman, Alan Ruck, Todd Field, and Jeremy Davies as a group of amateur but spirited storm chasers trying to deploy a tornado research device during a severe outbreak in Oklahoma. Twister was officially released in theaters on May 10, 1996. It is notable for being the first film to be released on DVD in the United States.
A storm shelter or storm cellar is a type of underground bunker designed to protect the occupants from violent 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 structures.
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.
A multiple-vortex tornado is a tornado that contains several vortices revolving around, inside of, and as part of the main vortex. The only times multiple vortices may be visible are when the tornado is first forming or when condensation and debris are balanced such that subvortices are apparent without being obscured. They can add over 100 mph to the ground-relative wind in a tornado circulation and are responsible for most cases where narrow arcs of extreme destruction lie right next to weak damage within tornado paths.
Cyclone mitigation encompasses the actions and planning taken before a tropical cyclone strikes to mitigate damage and injury from the storm. Knowledge of tropical cyclone impacts on an area help plan for future possibilities. Preparedness may involve preparations made by individuals as well as centralized efforts by governments or other organizations. Tracking storms during the tropical cyclone season helps individuals know current threats. Regional Specialized Meteorological Centers and Tropical Cyclone Warning Centers provide current information and forecasts to help individuals make the best decision possible.
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.
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 reported during the two-day outbreak, of which 14 were recorded as strong or violent. The outbreak claimed no fatalities and there were only 12 injuries from a tornado that touched down near Clinton, Oklahoma causing significant damage. The tornado outbreak overall left $32.8 million in damage.
Tornadoes have been recorded on all continents except Antarctica and 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, particularly with southward extent. 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 southeast Brazil, northern Mexico, New Zealand, and far eastern Asia.
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. 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 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. On May 27, 2013, the TIV2 filmed the inside of a tornado in Kansas with Casey inside.
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.
On the evening of Monday, May 3, 1999, a large and exceptionally powerful F5 tornado registered the highest wind speeds ever measured globally; winds were recorded at 301 ± 20 miles per hour (484 ± 32 km/h) by a Doppler on Wheels (DOW) radar. Considered the strongest tornado ever recorded to have affected the metropolitan area, the tornado devastated southern portions of Oklahoma City, Oklahoma, along with surrounding suburbs and towns to the south and southwest. 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.
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.
During the early evening of Friday, May 31, 2013, a very large and powerful tornado occurred over rural areas of Central Oklahoma. 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 up to 302 mph (486 km/h) within the vortex; these are the highest observed wind speeds on Earth, ahead of the 1999 Bridge Creek–Moore tornado with slightly higher wind speeds. As it crossed U.S. 81, it had grown to a record-breaking width of 2.6 miles (4.2 km). 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.
