A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud Cumulonimbus is a type of cloud that is tall, dense, and involved in thunderstorms and other intense weather. It is a result of atmospheric instability. These clouds can form alone, in clusters, or along a cold front in a squall line. They create lightning through the heart of the cloud. Cumulonimbus clouds form from cumulus clouds (namely from or, in rare cases, the base of a cumulus cloud Cumulus clouds are a type of cloud with noticeable vertical development and clearly defined edges. Cumulus means "heap" or "pile" in Latin. They are often described as "puffy" or "cotton-like", or "poofy" in appearance. Cumulus clouds may appear alone, in lines, or in clusters. Cumulus clouds are. Tornadoes come in many shapes and sizes, but are typically in the form of a visible condensation funnel A funnel cloud is a funnel-shaped cloud of condensed water droplets, associated with a rotating column of wind and extending from the base of a cloud but not reaching the ground or a water surface. A funnel cloud is usually visible as a cone-shaped or needle like protuberance from the main cloud base. Funnel clouds form most frequently in, whose narrow end touches the earth and is often encircled by a cloud of debris Debris is rubble, wreckage, ruins, litter and discarded garbage/refuse/trash, scattered remains of something destroyed, or, in geology, large rock fragments left by a melting glacier etc. The singular form of debris is debris. Depending on context, debris can refer to a number of different things and dust Dust is a general name for solid particles with diameters less than 20 thou . Particles in the atmosphere arise from various sources such as soil dust lifted up by wind, volcanic eruptions, and pollution. Dust in homes, offices, and other human environments contains small amounts of plant pollen, human and animal hairs, textile fibers, paper. Most tornadoes have wind speeds less than 110 miles per hour (177 km/h), are approximately 250 feet (80 m) across, and travel a few miles (several kilometers) before dissipating. The most extreme can attain wind speeds of more than 300 mph (480 km/h), stretch more than two miles (3 km) across, and stay on the ground for dozens of miles (more than 100 km).[1][2][3]

Various types of tornadoes include the landspout A landspout is a slang-term coined by meteorologist Howard B. Bluestein in 1985 for a kind of tornado not associated with the mesocyclone of a thunderstorm. The Glossary of Meteorology defines a landspout as, multiple vortex tornado, and waterspout. Waterspouts A waterspout is an intense columnar vortex that occurs over a body of water and is connected to a cumuliform cloud. In the common form, it is a non-supercell tornado over water. While it is often weaker than most of its land counterparts, stronger versions spawned by mesocyclones do occur. Waterspouts do not suck up water; the water seen in the are characterized by a spiraling funnel-shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non-supercellular A supercell is a thunderstorm that is characterized by the presence of a mesocyclone; a deep, continuously-rotating updraft. Of the four classifications of thunderstorms , supercells are the overall least common and have the potential to be the most severe. Supercells are often isolated from other thunderstorms, and can dominate the local climate tornadoes that develop over bodies of water.[4] These spiraling columns of air frequently develop in tropical areas close to the equator An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass. The capitalized term Equator refers to the Earth's equator, and are less common at high latitudes.[5] Other tornado-like phenomena that exist in nature include the gustnado A gustnado is a specific type of short-lived, low-level cyclonic cloud that can form in a severe thunderstorm. The name is a portmanteau of "gust front tornado", as gustnadoes form due to non-tornadic cyclonic features in the downdraft from the gust front of a strong thunderstorm, especially one which has become outflow dominated. It has, dust devil A dust devil is a strong, well-formed, and relatively long-lived whirlwind, ranging from small to large (more than 10 meters wide and more than 1000 meters tall). The primary vertical motion is upward. Dust devils are usually harmless, but rare ones can grow large enough to threaten both people and property, fire whirls A fire whirl, colloquially fire devil or fire tornado, is a rare phenomenon in which a fire, under certain conditions , acquires a vertical vorticity and forms a whirl, or a tornado-like vertically oriented rotating column of air. Fire whirls may be whirlwinds separated from the flames, either within the burn area or outside it, or a vortex of, and steam devil A steam devil is the term used to describe a rotating updraft that involves steam or smoke. Steam devils usually occur above power plants, and rarely occur elsewhere, though they may occur in deserts or other dry and arid locations. Hot springs may also be a suitable area for a steam devil to form. Cold air steam devils have also been reported,.

Tornadoes have been observed on every continent except Antarctica. However, the vast majority of tornadoes in the world occur in the Tornado Alley Tornado Alley is a colloquial and popular media term that most often refers to the area of the United States where tornadoes are most frequent. Although an official location is not defined, the area between the Rocky Mountains and Appalachian Mountains is usually associated with it region of the United States ^ b. English is the de facto language of American government and the sole language spoken at home by 80% of Americans age five and older. Spanish is the second most commonly spoken language, although they can occur nearly anywhere in North America.[6] They also occasionally occur in south-central and eastern Asia, the Philippines The Philippines , officially known as the Republic of the Philippines (Filipino: Republika ng Pilipinas), is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam. The Sulu Sea to the southwest lies between the country and the island of Borneo, and, northern and east-central South America, Southern Africa Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English, northwestern and southeast Europe, western and southeastern Australia, and New Zealand.[7] Tornadoes can be detected before or as they occur through the use of Pulse-Doppler radar Pulse-Doppler is a radar system capable of not only detecting target location , but also measuring its radial velocity (range-rate). It uses the Doppler effect to determine the relative velocity of objects; pulses of RF energy returning from the target are processed to measure the frequency shift between carrier cycles in each pulse and the by recognizing patterns in velocity and reflectivity data, such as hook echoes, as well as by the efforts of storm spotters.

There are several different scales for rating the strength of tornadoes. The Fujita scale The Fujita scale , or Fujita-Pearson scale, is a scale for rating tornado intensity, based 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 and/or aerial damage survey; and depending on the circumstances, ground-swirl patterns rates tornadoes by damage caused, and has been replaced in some countries by the updated Enhanced Fujita Scale The Enhanced Fujita Scale rates the strength of tornadoes in the United States based on the damage they cause. An F0 or EF0 tornado, the weakest category, damages trees, but not substantial structures. An F5 or EF5 tornado, the strongest category, rips buildings off their foundations and can deform large skyscrapers A skyscraper is a tall, continuously habitable building. There is no official definition or height above which a building may clearly be classified as a skyscraper. Most cities define the term empirically; even a building of 80 meters may be considered a skyscraper if it protrudes above its built environment and changes the overall skyline.[. The similar TORRO scale The TORRO tornado intensity scale is a scale measuring tornado intensity between T0 and T11. It was developed 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 ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes.[8] Doppler radar A weather radar, or weather surveillance radar , is a type of radar used to locate precipitation, calculate its motion, estimate its type (rain, snow, hail, etc.), and forecast its future position and intensity data, photogrammetry Photogrammetry is the practice of determining the geometric properties of objects from photographic images. Photogrammetry is as old as modern photography and can be dated to the mid-nineteenth century, and ground swirl patterns (cycloidal A cycloid is the curve defined by the path of a point on the edge of circular wheel as the wheel rolls along a straight line. It is an example of a roulette, a curve generated by a curve rolling on another curve marks) may also be analyzed to determine intensity and assign a rating.[9]

Contents
Part of the Nature Nature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general. It ranges in scale from the subatomic to the cosmic series on Weather Weather is the state of the atmosphere as measured on a scale of hot or cold, wet or dry, calm or storm, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate is the term for the average atmospheric conditions
Calendar Seasons A season is a division of the year, marked by changes in weather, ecology, and hours of daylight
Spring Spring is one of the four temperate seasons, the transition period between winter and summer. Spring and "springtime" refer to the season, and broadly to ideas of rebirth, renewal and regrowth. The specific definition of "spring" as a season differs, however, among scientific disciplines such as astronomy and meterorology, and · Summer Summer is the warmest of the four temperate seasons, between spring and autumn. It is marked by the longest days and shortest nights. The seasons start on different dates in different cultures based on astronomy and regional meteorology. However, when it is summer in the southern hemisphere it is winter in the northern hemisphere, and vice versa

Autumn Autumn is one of the four temperate seasons. Autumn marks the transition from summer into winter, usually in March (Southern Hemisphere) or September (Northern Hemisphere) when the arrival of night becomes noticeably earlier · Winter Winter is the coldest season of the year, between autumn and spring, marked by the shortest days and longest nights
Tropical Seasons The tropics is a region of the Earth by the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately 23° 26′ 16″ N and the Tropic of Capricorn in the southern hemisphere at 23° 26′ 16″ ( or 23.438° ) S. The tropics are also referred to as the tropical zone and the torrid zone (see

Dry season The dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year. The tropical rain belt lies in the southern hemisphere roughly from October to March, and during this time the · Wet season The wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region falls. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the tropics and subtropics. In contrast to areas with savanna
Storms A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather. It may be marked by strong wind, thunder and lightning (a thunderstorm), heavy precipitation, such as ice (ice storm), or wind transporting some substance through the atmosphere (as in a dust storm, snowstorm,

Thunderstorm A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically-assigned cloud type associated with the thunderstorm is the cumulonimbus. Thunderstorms are · Supercell A supercell is a thunderstorm that is characterized by the presence of a mesocyclone; a deep, continuously-rotating updraft. Of the four classifications of thunderstorms , supercells are the overall least common and have the potential to be the most severe. Supercells are often isolated from other thunderstorms, and can dominate the local climate Downburst A downburst is created by an area of significantly rain-cooled air that, after hitting ground level, spreads out in all directions producing strong winds. Unlike winds in a tornado, winds in a downburst are directed outwards from the point where it hits land or water. Dry downbursts are associated with thunderstorms with very little rain, while · Lightning Lightning is an atmospheric discharge of electricity accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms. In the atmospheric electrical discharge, a leader of a bolt of lightning can travel at speeds of 60,000 m/s , and can reach temperatures approaching 30,000 °C (54,000 °F) Tornado · Waterspout A waterspout is an intense columnar vortex that occurs over a body of water and is connected to a cumuliform cloud. In the common form, it is a non-supercell tornado over water. While it is often weaker than most of its land counterparts, stronger versions spawned by mesocyclones do occur. Waterspouts do not suck up water; the water seen in the Tropical cyclone (Hurricane) A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones feed on heat released when moist air rises, resulting in condensation of water vapor contained in the moist air. They are fueled by a different heat mechanism than other cyclonic Extratropical cyclone Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and horizontal gradients in temperature and dew point Winter storm A winter storm is an event in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form . In temperate continental climates, these storms are not necessarily restricted to the winter season, but may occur in the · Blizzard A blizzard is a severe storm condition characterized by low temperatures, strong winds, and heavy snow. By definition, the difference between blizzard and a snowstorm is the strength of the wind. Ground blizzards are a variation on the traditional blizzard, in that ground blizzards require high winds to stir up snow that has already fallen, rather · Ice storm An ice storm is a type of winter storm characterized by freezing rain, also known as a glaze event or in some parts of the United States as a silver thaw. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least 0.25-inch of ice on exposed surfaces. From 1982 to 1994, ice storms were more Dust storm A dust storm or sandstorm is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front blows loose sand and dust from a dry surface. Particles are transported by saltation and suspension, causing soil erosion from one place and deposition in another. The Sahara and drylands around the Arabian peninsula · Firestorm A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires, forest fires, and wildfires. The Black Saturday bushfires, the Great Peshtigo Fire and the Ash Wednesday fires are examples of firestorms. Firestorms · Cloud A cloud is a visible mass of droplets of water or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. A cloud is also a visible mass attracted by gravity, such as masses of material in space called interstellar clouds and nebulae. Clouds are studied in the nephology or cloud physics branch of
Precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that is pulled down by gravity and deposited on the Earth's surface. The main forms of precipitation include rain, snow, ice pellets, and graupel. It occurs when the atmosphere, a large gaseous solution, becomes saturated with water vapour and the water

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Etymology

The word tornado is an altered form of the Spanish word tronada, which means "thunderstorm". This in turn was taken from the Latin tonare, meaning "to thunder". It most likely reached its present form through a combination of the Spanish tronada and tornar ("to turn"); however, this may be a folk etymology.[10][11] A tornado is also commonly referred to as a "twister", and is also sometimes referred to by the old-fashioned colloquial term cyclone.[12][13] The term "cyclone" is used as a synonym for "tornado" in the often-aired 1939 film, The Wizard of Oz. The term "twister" is also used in that film, along with being the title of the 1996 tornado-related film Twister.

Definitions

A tornado near Seymour, Texas

A tornado is "a violently rotating column of air, in contact with the ground, either pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud".[14] For a vortex to be classified as a tornado, it must be in contact with both the ground and the cloud base. Scientists have not yet created a complete definition of the word; for example, there is disagreement as to whether separate touchdowns of the same funnel constitute separate tornadoes.[3] Tornado refers to the vortex of wind, not the condensation cloud.[15][16]

Funnel cloud

Main article: Funnel cloud This tornado has no funnel cloud; however, the rotating dust cloud indicates that strong winds are occurring at the surface, and thus it is a true tornado.

A tornado is not necessarily visible; however, the intense low pressure causing the high wind speeds (as described by Bernoulli's principle) and rapid rotation (due to cyclostrophic balance) usually causes water vapor in the air to become visible as a funnel cloud or condensation funnel.[17]

There is some disagreement over the definition of funnel cloud and condensation funnel. According to the Glossary of Meteorology, a funnel cloud is any rotating cloud pendant from a cumulus or cumulonimbus, and thus most tornadoes are included under this definition.[18] Among many meteorologists, the funnel cloud term is strictly defined as a rotating cloud which is not associated with strong winds at the surface, and condensation funnel is a broad term for any rotating cloud below a cumuliform cloud.[3]

Tornadoes often begin as funnel clouds with no associated strong winds at the surface, although not all evolve into a tornado. However, many tornadoes are preceded by a funnel cloud. Most tornadoes produce strong winds at the surface while the visible funnel is still above the ground, so it is difficult to discern the difference between a funnel cloud and a tornado from a distance.[3]

Outbreaks and families

Main articles: Tornado family, tornado outbreak, and tornado outbreak sequence

Occasionally, a single storm will produce more than one tornado, either simultaneously or in succession. Multiple tornadoes produced by the same storm cell are referred to as a "tornado family".[19] Several tornadoes are sometimes spawned from the same large-scale storm system. If there is no break in activity, this is considered a tornado outbreak, although there are various definitions. A period of several successive days with tornado outbreaks in the same general area (spawned by multiple weather systems) is a tornado outbreak sequence, occasionally called an extended tornado outbreak.[14][20][21]

Characteristics

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'Tornadoes' News
Recovery assistance following May tornadoes tops $10 million - KTEN
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tops $10 million kten oklahoma city - Ten weeks after the president's disaster declaration for Oklahoma's May 10-13 storms and tornadoes , state and federal assistance to help ... fema storm grants top ten million kokc
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CHICAGO (Reuters) - Powerful storms spawned by intense heat and humidity produced flooding and . tornadoes. in the Midwestern United States on Saturday, disrupting.

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'Tornadoes' Answers
What is it about the 'attraction' between tornadoes and mobile home parks?
Q. Again, in the news, a mobile home park is struck by a tornado. Is it me, or does it seem tornadoes always strike mobile home parks and pass everything else?
Asked by commonsense - Thu Nov 16 14:39:12 2006 - - 6 Answers - 1 Comments

A. well, have you ever been to a mobile home park? there are no trees or buildings around and it's very VERY windy. so, it's very easy for tornadoes to form. most tornadoes form in an open field. you never see one forming above trees.
Answered by Pearlz - Thu Nov 16 14:42:53 2006

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