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Tornado

A tornado is a violently rotating column of air which is in contact with both a cumulonimbus Cumulonimbus cloud

Cumulonimbus is a type of cloud [i] that is tall, dense, and involved in thunderstorm [i]s and other ba ... 

  cloud base and the surface of the earth. Tornadoes can come in many shapes, but are typically in the form of a visible condensation funnel, with the narrow end touching the earth. Often, a cloud of debris encircles the lower portion of the funnel. Tornadoes can be very destructive. Most have winds of 110 mph or less, are approximately 250 feet across, and travel a few miles before dissipating. However, some tornadoes can have winds of more than 300 mph , be more than a mile across, and stay on the ground for dozens of miles .

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Timeline

1680   The first documented tornado in America kills a servant at Cambridge, Massachusetts Cambridge, Massachusetts

Cambridge is a city [i] in the Greater Boston [i] area of Massachusetts [i], United States [i]. ... 

.

1879   A F4 Fujita scale

The Fujita scale, or Fujita-Pearson scale, rates a tornado [i]'s intensity by the damage it inflic ... 

 tornado struck Irving, Kansas Kansas

Kansas is a Midwestern [i] state [i] in the Central [i] United States [i] ... 

, killing 18 people and injuring 60.

1890   A tornado strikes Louisville, Kentucky Louisville, Kentucky

Louisville is Kentucky [i]'s largest city [i]. ... 

, killing 76 people and injuring 200.

1917   Tornado strikes Mattoon, Illinois Illinois

Illinois is the 21st U.S. state [i] and is located in the Midwest [i] region o ... 

 causing devastation and killing 101 people.

1932   Tornado and huge waves kills about thousand in Santa Crus del Sure in Cuba Cuba

Cuba, officially the Republic of Cuba, consists of the island of Cuba, the Isle of Youth [i] and a ... 

1933   Tornado destroys the town of Tampico Tampico

Tampico, located at , is the main city in the state [i] of Tamaulipas [i], Mexico [i], ... 

 in Mexico Mexico

The United Mexican States, generally known as Mexico is a country [i] located in North America [i] ... 

.

1934   Tornado in Osaka Osaka

listen is the capital of Osaka Prefecture [i] and the third-largest city [i] in Japan [i], wi ... 

 and Kyoto Kyoto

is a city [i] in Japan [i], which has a population close to 1.5 million. ... 

 and destroys the rice harvest - 1660 dead, 5400 injured

1953   Flint-Worcester Tornadoes: A tornado hits in Flint, Michigan Flint, Michigan

Flint, Michigan is a city in the U.S. state [i] of Michigan [i], located along the Flint River [i] ... 

 and kills 115. This is the last tornado to claim more than 100 lives.

1971   Fifty tornadoes rage in Mississippi Mississippi

Mississippi is a southern [i] state [i] of the United States [i]. ... 

, killing 74.

1974   The Super Outbreak, the largest series of tornadoes in history, hits 13 U.S. states and one Canadian provin By the time the last of 149 tornadoes hit early the following morning, 315 die and over 5,000 are injured.

   More Events >>



Encyclopedia


A tornado is a violently rotating column of air which is in contact with both a cumulonimbus Cumulonimbus cloud

Cumulonimbus is a type of cloud [i] that is tall, dense, and involved in thunderstorm [i]s and other ba ... 

  cloud base and the surface of the earth. Tornadoes can come in many shapes, but are typically in the form of a visible condensation funnel, with the narrow end touching the earth. Often, a cloud of debris encircles the lower portion of the funnel.

Tornadoes can be very destructive. Most have winds of 110 mph or less, are approximately 250 feet across, and travel a few miles before dissipating. However, some tornadoes can have winds of more than 300 mph , be more than a mile across, and stay on the ground for dozens of miles .

They have been observed on every continent except Antarctica Antarctica

Antarctica is the southernmost continent and encompasses the South Pole [i]. ... 

; a significant percentage of the world's tornadoes occur in the United States United States

The United States of America, also known as the United States, the U.S., the U.S.A., a... 

. This is mostly due to the unique geography of the country, which allows the conditions which breed strong, long-lived storms to occur many times a year. Other areas which commonly experience tornadoes include Australia Australia

Australia, officially the Commonwealth of Australia, is a country in the Southern Hemisphere [i] c ... 

, south-central Canada Canada

Canada is the world's second-largest [i] country by total area, occupying most ... 

, northwestern Europe Europe

Europe is one of the seven traditional continent [i]s of the Earth [i]. ... 

, south-central and eastern Asia Asia

Asia is the largest and most populous continent [i] or region, depending on the definition.... 

, east-central South America South America

South America is a continent [i] situated in the western hemisphere [i] and, mostly, ... 

, and South Africa South Africa

The Republic of South Africa is a country located at the southern tip of the Africa [i]n continent [i]. ... 

..

Etymology

The word "tornado" is an altered form of the Spanish Spanish language

Spanish or Castilian is an Iberian Romance language [i]. ... 

 word tronada, which means "thunderstorm Thunderstorm

A thunderstorm, or an electrical storm [i], is a form of weather [i] characterized by the presence ... 

". This in turn was taken from the Latin Latin

Latin is an ancient Indo-European language [i] originally spoken in Latium [i], ... 

 tronar, meaning "to thunder Thunder

Thunder is, even today, not completely understood by modern science.... 

". It most likely reached its present form through a combination of the Spanish tronada and tornar ; however, this may be a folk etymology.

Some common, related slang terms include: twister, whirlwind, cyclone, funnel, wedge, finger of God, Devil's tail, rope, or stovepipe. The word willy-willy is also rarely applied to tornadoes, however, the usual definition of the term is of a dust devil Dust devil

A dust devil or whirlwind is a rotating updraft, ranging from small to large .... 

 in Australia.

Definitions




A tornado is defined by the National Weather Service National Weather Service

The National Weather Service is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration [i] ... 

  as "a violently rotating column of air in contact with the ground and extending from a thunderstorm base." A tornado does not necessarily have to be visible; however, the low pressures caused by the fast wind speeds usually cause water vapor in the air to condense into a visible condensation funnel.funnel cloud Funnel cloud

A funnel cloud is a funnel [i]-shaped cloud [i] of condensed [i] water [i] droplets, associ ... 

 is a low-hanging, rotating cloud, with no associated strong winds at the surface. Funnel clouds are not tornadoes, however, many tornadoes initially descend from the parent storm as a funnel cloud. It is often difficult to tell the difference between a funnel cloud and a tornado from a distance. Many tornadoes can produce strong winds at the surface while the visible funnel is still a good distance from the ground.nger tornadoes are often observed to have multiple vortices Multiple vortex tornado

A multiple vortex tornado is a tornado [i] that contains several vortices rotating around and inside ... 

, or many columns of violently spinning air rotating around a common center. However, a satellite tornado is a term for a weak tornado which forms very near a large, strong tornado, often lasting no more than a minute. The satellite tornado may appear to "orbit" the larger tornado , giving the appearance of one, large multi-vortex tornado. However, a satellite tornado is a distinct funnel, and is much smaller than the main funnel.waterspout Waterspout

A waterspout is an intense columnar vortex that occurs over a body of water and is connected to a cumuli... 

 is a tornado over water. In general, most tornadoes over land are associated with a severe thunderstorm; however, the National Weather Service in the United States considers all waterspouts—including "fair weather" waterspouts—to be tornadoes. These less severe relatives of classic tornadoes are almost always weak , and spawn from non-rotating thunderstorms, or even regular summer showers. Typically, waterspouts moving onto land cause little or no damage, and dissipate within minutes. However, strong waterspouts from supercell Supercell

A supercell is a severe thunderstorm [i] with a deep rotating updraft [i] . ... 

s can cause significant damage if they impact land areas. In addition, strong tornadoes can move over lakes or over the ocean, becoming waterspouts, without losing intensity.

A landspout Landspout

A landspout is a slang-term used by storm chaser [i]s for a tornado [i] not associated with the mesocyclone [i] ... 

is an unofficial term for a tornado not associated with a mesocyclone Mesocyclone

A mesocyclone is a large area of vertically spiraling air, usually associated with a supercell thunderstorm [i] ... 

. Known officially as a dust-tube tornado, it is usually weak, features a small condensation funnel which often does not appear to reach the ground, and is often marked by a tall tube of dust and/or debris reaching as far up as the parent cloud. Though usually weaker than ordinary tornadoes, they are tornadoes, and can cause serious damagegustnado is a small, vertical swirl associated with a gust front Outflow boundary

An outflow boundary is a storm-scale [i] or mesoscale [i] boundary separating thunderstorm [i] ... 

 or downburst Downburst

A downburst is a column of sinking air that is capable of producing damaging straight-line winds of ... 

. Because they are technically not associated with the cloud base, there is some debate as to whether or not gustnadoes are actually tornadoes.dust devil Dust devil

A dust devil or whirlwind is a rotating updraft, ranging from small to large .... 

is also a vertical swirling column of air. These phenomena resemble tornadoes, but are rarely as strong as even the weakest tornadoes, and tend to form under clear skies. Dust devils are not considered tornadoes because they form during fair weather, and are not associated with thunderstorms. However, they can, on occasion, result in major damage and fatalities, especially in arid areas.


Life cycle

Most tornadoes follow a recognizable life cycle.

Characteristics





Shape

Most tornadoes take on the traditional appearance of a narrow funnel Funnel

A funnel is a conically shaped pipe, employed as a device to channel liquid [i] or fine-grained substanc ... 

, a few hundred yards across, with a small cloud of debris Debris

Debris is a word used to describe the remains of something that has been otherwise destroyed.... 

 near the ground. However, tornadoes can appear in all manner of shapes and sizes.

Small, relatively weak landspouts might only be visible as a small swirl of dust on the ground. While the condensation funnel may not extend all the way to the ground, if associated surface winds are greater than 40 mph , it is considered a tornado.

Large single-vortex twisters, often violent, can look like a large wedge stuck into the ground, and are known as wedge tornadoes or wedges. Wedges can be so wide that they appear to be a block of dark clouds. Even experienced storm observers may not be able to tell the difference between a low-hanging cloud and a wedge tornado from a distance.

Tornadoes in the dissipating stage can appear like narrow tubes, or ropes, twisting into all manner of curls, twists, and s-shapes. These tornadoes, such as the one pictured at right, are roping out, or becoming a rope tornado. Multiple-vortex tornadoes can appear as a family of swirls circling a common center, or may be completely obscured by condensation, dust, and debris, appearing to be a single funnel.

In addition to these appearances, tornadoes may be obscured completely by rain or dust. These tornadoes are especially dangerous, as even experienced meteorologists might not spot them.Size


In the United States, an average tornado is around 500 feet across, and stays on the ground for 5 miles . While this is the average, there is an extremely wide range of tornado sizes, even for typical tornadoes.

Weak tornadoes, or strong but dissipating tornadoes, can be exceedingly narrow, sometimes only a few feet across. In fact, a tornado was once reported to have a damage path only 7 feet long.he other end of the spectrum, wedge tornadoes can have a damage path a mile wide or more. A tornado which affected Hallam, Nebraska Hallam, Nebraska Tornado Outbreak

The Hallam, Nebraska Tornado Outbreak was an outbreak [i] of over 20 tornado [i]es in Nebraska [i] ... 

 on May 22, 2004 was at one point 2.5 miles wide.

In terms of path length, some meteorologists believe that the Tri-State Tornado Tri-State Tornado

The Great Tri-State Tornado of Wednesday, March 18 [i], 1925 [i], crossed from southeastern Missouri [i] ... 

, which affected parts of Missouri Missouri

Missouri named after the Missouri Siouan [i] Indian tribe meaning "town of the large canoes", is a cent... 

, Illinois Illinois

Illinois is the 21st U.S. state [i] and is located in the Midwest [i] region o ... 

, and Indiana Indiana

Indiana, meaning the "Land of the Indians [i]," is a state i ... 

 on March 18, 1925, was on the ground continuously for 219 miles . However, without a modern damage survey, it is impossible to determine whether or not the deadly event was a single tornado or a series of violent tornadoes produced by the same storm. The longest modern-day damage path was caused by a tornado which was on the ground for 160 miles in northeastern North Carolina North Carolina

North Carolina is a state [i] in the Southeastern [i] United States [i]... 

 on November 22, 1992.

Appearance


Tornadoes, depending on the environment in which they form, can have a wide range of colors. Tornadoes which form in a dry environment can be nearly invisible, marked only by swirling debris at the base of the funnel. Condensation funnels which pick up little or no debris can be grey to white. While travelling over a body of water as a waterspout, they can turn very white or even blue. Funnels which move slowly, ingesting a lot of debris and dirt, are usually darker, taking on the color of debris. Tornadoes in the Great Plains Great Plains

The Great Plains is the broad expanse of prairie [i] and steppe [i] which lies east of the Rocky Mountains [i] ... 

 can turn red because of the reddish tint of the soil, and tornadoes in mountainous areas can travel over snow-covered ground, turning brilliantly white in the process.



Lighting conditions are also a major factor in the appearance of a tornado. A tornado which is "back-lit", or viewed with the sun behind it, will appear to be very dark. The same tornado, viewed with the sun at the observer's back, may appear grey or brilliant white. Tornadoes which occur near the time of sunset can be many different colors, appearing in hues of yellow, orange, and pink.

Dust kicked up by the winds of the parent thunderstorm, heavy rain and hail, and the darkness of night are all factors which can reduce the visibility of tornadoes, making them "invisible", in essence. Tornadoes occurring in these conditions are especially dangerous, since only radar observations, or possibly the sound of an approaching tornado, serve as any warning to those in the storm's path. Fortunately most significant tornadoes form under the storm's rain-free base, or the area under the thunderstorm's updraft, where there is little or no rain. In addition, most tornadoes occur between the hours of 4 and 8 pm, when the bright sun can penetrate even the thickest clouds. Also, night-time tornadoes are often illuminated by frequent lightning.

There is mounting evidence, including doppler radar images and eyewitness accounts, which suggest that most tornadoes have a clear, calm center with extremely low pressure, akin to the eye found in tropical cyclone Tropical cyclone

In meteorology [i], a tropical cyclone is a storm system fueled by the heat released when moist air rise ... 

s. This area would be clear , have relatively light winds, and be very dark, with the light blocked out by swirling debris on the outside of the tornado. Lightning is said to be the source of illumination for those who claim to have seen the interior of a tornado.

Rotation


Tornadoes normally rotate in a cyclonic Cyclone

In meteorology [i], a cyclone is the rotation of a volume of air around an area of low atmospheric pressure [i] ... 

 direction . Large-scale storms always rotate cyclonically because of the Coriolis effect Coriolis effect

The Coriolis effect is an apparent deflection of a moving object in a rotating frame of reference [i].
... 

; however, tornadoes are too small in scale to be directly affected by the rotation of the earth. Approximately 1 tornado in 100 rotates in an anticyclonic direction. Typically, only landspouts and gustnados also rotate anticyclonically. However, on very rare occasions, an anticyclonic supercell can develop, producing a tornado that is typical except for its direction of rotation.

Intensity and damage


Tornadoes vary in intensity regardless of shape, size, and location. While strong tornadoes are typically larger than weak tornadoes, there are several instances of F5 tornadoes with damage paths less than 500 feet wide. istory of tornado intensity measurementsFor many years, before the advent of home movies and doppler radar, scientists had nothing more than educated guesses as to the speed of the winds in a tornado. The only evidence indicating the wind speeds found in the tornado was the damage left behind by tornadoes which struck populated areas. Some thought they might exceed 500 mph, and perhaps even be supersonic.

In the 1950s, however, evidence mounted that the actual wind speeds were much lower than this. On April 2, 1957, a slow moving tornado traversed the south and east parts of Dallas, Texas Dallas, Texas

Dallas is the third-largest city in the state of Texas [i] and the ninth-largest [i] ... 

. Before this day, only a few photographs and motion picture Film

Film is a term that encompasses motion pictures as individual projects, as well as the field in general.... 

s of tornadoes were known to exist. However, because of many factors, including the tornado's high visibility, slow forward motion, and proximity to an urban center, it became the most filmed and photographed tornado in history. Frame-by-frame analysis of several pieces of footage taken that day showed that the debris flung about by the tornado was travelling at speeds up to 170 mph.ear}}

In 1971, Dr. Tetsuya Theodore Fujita introduced the idea for a scale of tornado winds. With the help of colleague Allen Pearson, he created and introduced what came to be called the Fujita scale Fujita scale

The Fujita scale, or Fujita-Pearson scale, rates a tornado [i]'s intensity by the damage it inflic ... 

 in 1973. The scale was based on a relationship between the Beaufort scale and the Mach number Mach number

Mach number is defined as a ratio of the speed [i] of an object or flow relative to the speed of sound [i] ... 

 scale; the low end of F1 on his scale corresponds to the low end of B12 on the Beaufort scale, and the low end of F12 corresponds to the speed of sound at sea level, or Mach 1. In practice, tornadoes are only assigned categories F0 through F5.

The TORRO scale, developed by the Tornado and Storm Research Organisation , was developed in 1974, and published a year later. The TORRO scale has 12 levels, which cover a broader range with tighter graduations. It ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes.

There is some debate as to the usefulness of the TORRO scale over the Fujita scale—while it may be helpful for statistical purposes to have more levels of tornado strength, often the damage caused could be created by a large range of winds, rendering it hard to narrow the tornado down to a single TORRO scale category.

Research conducted in the late 1980s and 1990s suggested that, even with the implication of the Fujita scale, tornado winds were notoriously overestimated, especially in significant and violent tornadoes. Because of this, in 2006, the American Meteorological Society introduced the Enhanced Fujita Scale Fujita scale

The Fujita scale, or Fujita-Pearson scale, rates a tornado [i]'s intensity by the damage it inflic ... 

, to help assign realistic wind speeds to tornado damage. The scientists specifically designed the scale so that a tornado assessed on the Fujita scale and the Enhanced Fujita scale would receive the same ranking. The EF-scale is more specific in detailing the degrees of damage on different types of structures for a given wind speed. While the F-scale goes from F0 to F12 in theory, the EF-scale is capped at EF5, which is defined as "winds = 200 mph ".age:F0 tornado damage example.jpg|thumb|300px|right|An example of F0 damage. The only significant damage to structures in this picture was caused by tree branches which fell due to the tornado's winds. Even though well-built structures are typically unscathed by F0 tornadoes, falling trees and tree branches can injure and kill people, even when they are inside a sturdy structure.]]





The first observation which confirmed that F5 winds could occur happened on April 26, 1991. A tornado near Red Rock, Oklahoma was monitored by scientists using a portable Doppler radar, an experimental radar device that measures wind speed. Near the tornado's peak intensity, they recorded a wind speed of 115-120 m/s . Though the portable radar had uncertainty of ± 5-10 m/s , this reading was probably within the F5 range, confirming that tornadoes were capable of violent winds found nowhere else on earth.

Eight years later, during the Oklahoma Tornado Outbreak of May 3, 1999, another scientific team was monitoring an exceptionally violent tornado . At about 7 pm, they recorded one measurement of 318 mph ypical intensity


In the United States, F0 and F1 tornadoes account for 80% of all tornadoes. On the other hand, violent tornadoes , account for less than 1%. Worldwide, strong tornadoes account for an even smaller percentage of total tornadoes. Violent tornadoes are extremely rare outside of the United States and Bangladesh.

Typical damage



As stated in the lede section, a typical tornado has winds of 110 mph or less, is approximately 250 feet across, and travels a mile or so before dissipating. However, there is no such thing as a typical tornado.

Two tornadoes that look almost exactly the same can produce drastically different effects. Also, two tornadoes which look very different can produce similar damage. This is due to the fact that tornadoes form by several different mechanisms, and also that they follow a life cycle which causes the same tornado to change in appearance over time. People in the path of a tornado should never attempt to determine its strength as it approaches. Between 1997 and 2005 in the United States, 38 people were killed by F1 tornadoes, and 3 were killed by F0 tornadoes. Even the weakest tornado can kill.

  • Weak tornadoes

As stated in the previous section, an overwhelming majority of tornadoes are designated F1 or F0, also known as "weak" tornadoes. However, weak is a relative term for tornadoes, as even these can cause significant damage. F0 and F1 tornadoes are typically short-lived—since 1980 almost 75% of tornadoes rated weak stayed on the ground for one mile or less.0 damage is characterized by superficial damage to structures and vegitation. Well-built structures are typically unscathed, sometimes sustaining broken windows, with minor damage to roofs and chimney Chimney

[i], [[stove]... 

s. Billboards and large signs can be knocked down. Trees have large branches broken off, and can be uprooted if they have shallow roots.

F1 damage has caused significantly more fatalities than that caused by F0 tornadoes. At this level, damage to mobile homes and other temporary structures becomes significant, and cars and other vehicles can be pushed off the road. Permanent structures can suffer major damage to their roofs.

  • Significant tornadoes


F2 tornadoes are the lower end of "significant", and yet are stronger than most tropical cyclone Tropical cyclone

In meteorology [i], a tropical cyclone is a storm system fueled by the heat released when moist air rise ... 

s . Well-built structures can suffer serious damage, including roof loss and collapse of outer walls. Mobile homes, however, are almost totally destroyed. Vehicles can be lifted off the ground, and lighter objects can become small missiles, causing damage outside of the tornado's main path. Wooded areas will have a large percentage of their trees snapped or uprooted.

F3 damage is a serious risk to life and limb. Few parts of affected buildings are left standing; well-built structures lose outer and inner walls. Cars are lifted off the ground, and can be tossed through the air for some distance. Wooded areas will suffer almost total loss of vegitation.

  • Violent tornadoes


F4 damage typically results in a total loss of the affected structure. Well-built homes are reduced to a short pile of debris. Even heavy vehicles can become airborne, with very large projectiles being flung some distance.

F5 damage is almost always total. F5 tornadoes demolish well-built houses and sweep the foundation clean. The official description of this damage states that "incredible phenomena will occur". In history, F5 tornadoes have twisted skyscrapers, levelled entire communities Jarrell Tornado

The Jarrell Tornado was the F5 [i] tornado that struck the town of Jarrell, Texas [i], on May 27 [i] ... 

, and stripped asphalt from the ground.

Prediction and detection



United States


In the United States, severe weather predictions are issued by the Storm Prediction Center Storm Prediction Center

The Storm Prediction Center, located in Norman, Oklahoma [i], is part of the National Centers for Environmental Prediction [i]... 

, based in Norman, Oklahoma Norman, Oklahoma

Norman is the largest city in Cleveland County [i] in the U.S. state [i] of Oklahoma [i] ... 

. Issued for the next three days, as well as for the four through eight day period, they will determine the probability of severe weather, including tornadoes. The SPC uses computer models Numerical weather prediction

Numerical weather prediction is the science of predicting the weather [i] using "models" of the atmosphe ... 

, such as the NAM, GFS, WRF, and RUC to predict severe weather. They issue their outlooks based on data from these models, using such indicies as Lifted Index, CAPE, as well as temperature and dewpoint.

Warnings are issued by the regional National Weather Service National Weather Service

The National Weather Service is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration [i] ... 

 offices, while watches are issued directly from the SPC.

The National Weather Service trains Skywarn Skywarn

SKYWARN is a program of the United States [i]'s National Weather Service [i] ... 

 spotters, consisting of local sheriff's deputies Sheriff

Sheriff is both a political [i] and a legal [i] office held under English common law [i] ... 

, state troopers, and ordinary citizens, to spot key features of storms which indicate severe hail, strong winds, and tornadoes. When severe weather is anticipated, local weather service offices request that these spotters be on the lookout for severe weather, and report any possible tornadoes immediately, so the office can issue a timely warning.

United Kingdom


In the United Kingdom, the Tornado and Storm Research Organisation  makes experimental predictions.

Other countries


In the Japan Japan

is an island country [i] in East Asia [i]. ... 

, predictions and study of tornadoes in Japan are handled by the Japan Meteorological Agency Japan Meteorological Agency

The or JMA, is the Japanese government's [i] weather [i] service. ... 

.

Climatology

Geography


The UK United Kingdom

The United Kingdom of Great Britain and Northern Ireland is a country and sovereign state [i] tha ... 

 has the highest average number of recorded tornadoes per area of any country , but most are small and result in minor damage.
. Bangladesh Bangladesh

Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia [i]. ... 

 also suffers from tornadoes of equal severity to those in the USA but these tend to be less well reported because of the scarcity of media coverage. The annual human death toll at about 179 deaths per year from tornadoes in Bangladesh is however much greater than in the USA.

Frequency of occurrence



Time of occurrence


As stated in previously, worldwide statistics for tornado occurrences are intermittant at best, so data presented here may not be valid worldwide.

Tornado occurrence in the United States is highly dependant on the time of day.

Extremes


Tornadoes are the most violent weather events in the world. As such, they have been recorded to produce some incredible phenomena.

In terms of the most extreme tornado in history, the honor undoubtedly goes to the Tri-State Tornado Tri-State Tornado

The Great Tri-State Tornado of Wednesday, March 18 [i], 1925 [i], crossed from southeastern Missouri [i] ... 

 which roared through parts of Missouri Missouri

Missouri named after the Missouri Siouan [i] Indian tribe meaning "town of the large canoes", is a cent... 

, Illinois Illinois

Illinois is the 21st U.S. state [i] and is located in the Midwest [i] region o ... 

, and Indiana Indiana

Indiana, meaning the "Land of the Indians [i]," is a state i ... 

 on March 18, 1925. This tornado set records for the deadliest single United States tornado , longest path length , longest duration , and fastest forward speed for a significant tornado .

The deadliest tornado in world history occurred on April 26, 1989 in Bangladesh Bangladesh

Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia [i]. ... 

, killing 1300 people. pandsection}}

Tornado safety

Precautions


Though it is uncommon to get more than a few minutes warning before a tornado strikes, there are precautions and preventative measures that you can take in order to increase the chances of surviving a tornado.

In tornado-prone areas, most homes have a storm cellar Storm cellar

Storm cellars are underground structures that are either located below buildings, or are built undergrou... 

 on the property. These underground refuges have saved thousands of lives.

If a tornado approaches...


If a tornado approaches and you are outside, seek shelter immediately in a well structured building. If a building is out of your reach, drop in a ditch.

If on the road, try to look for shelter. If there isn't any near try to look for a ditch and stay there until the danger passes. Never try to outrun a twister, for it may cost you your life as it may take an unexpected turn.

If in a house or building, seek shelter in the basement. If the structure does not have a basement, or if the tornado's so close that it won't allow you to reach a basement, go to the most innermost part of the house, preferably and usually a bathroom, and lay in the bathtub or hang on to the plumbing.andsection}}

Myths and misconceptions


Continuing research

Though scientists have learned much from years of research, there are still many things about tornadoes which remain a mystery. In fact, scientists still don't know exactly how a rotation in the middle of the thunderstorm descends to become a tornado. Research programs, including VORTEX Vortex

A vortex is a spinning, often turbulent [i], flow with closed streamline [i]s. ... 

, deployment of TOTO TOtable Tornado Observatory

The TOtable Tornado Observatory was a large, instrumented metal barrel which scientists attempted to put... 

 , and dozens of other programs, hope to solve many questions that still plague meteorologists.

Social implications of tornadoes




Tornado damage to man-made structures is a result of the high wind velocity and windblown debris. Tornadic winds have been measured in excess of 300 mph . Tornado season in North America North America

North America is a continent [i] in the Earth [i]'s northern hemisphere [i] and almost fully in the western hemisphere [i]... 

 is generally March through November, although tornadoes can occur at any time of year. They tend to occur in the afternoons and evenings; over 80% of all tornadoes strike between noon and midnight.

Some individuals and hobbyist Hobby

A hobby is a spare-time [i] recreation [i]al pursuit.... 

s, known as storm chasers Storm chasing

Storm chasing is broadly defined as the intentional pursuit of any severe weather condition, regardless ... 

, enjoy pursuing thunderstorms and tornadoes to explore their many visual and scientific aspects. Attempts have been made by some storm chasers from educational and scientific institutions to drop probes in the path of oncoming tornadoes in an effort to analyze the interior of the storms, but only about five drops have been successful since around 1990.

Due to the relative rarity and large scale of destructive power that tornadoes possess, their occurrence or the possibility that they may occur can often create what could be considered sensationalism in their reporting. This results in so-called weather wars, in which competing local media outlets, particularly TV news stations, engage in continually escalating technological one-upsmanship and drama in order to increase their market share. This is especially evident in tornado-prone markets, such as those in the Great Plains.

According to Environment Canada Environment Canada

The Department of the Environment or Environment Canada [i] is the department [i] ... 

, the chances of being killed by a tornado are 12 million to 1 . One may revise this yearly and/or regionally, but the probability may be factually stated to be low. Tornadoes do cause millions of dollars in damage, both economic and physical, displacement, and many injuries every year.

Cultural significance

Tornadoes as a metaphor



The tornado has been used by cartoonist Cartoonist

A cartoonist is an artist [i] who specializes in drawing cartoon [i]s. ... 

s for over 100 years as a metaphor for political upheaval. For example, according to political interpretations Political interpretations of The Wonderful Wizard of Oz

The Wonderful Wizard of Oz [i] is a modernized fairy tale written by L. Frank Baum [i] and illustrat ... 

 of The Wizard of Oz, the tornado takes Dorothy Dorothy Gale

Dorothy Gale is a fictional character [i], the protagonist [i] of most of the Oz [i] novels b ... 

 to a utopia Utopia

Utopia, in its most common and general positive meaning, refers to an imaginary, ideal civilizatio... 

, the Land of Oz Land of Oz

Oz is an imaginary region containing four countries under the rule of one monarch.... 

, and kills the Wicked Witch of the East, who had oppressed a little people, the Munchkin Munchkin

Munchkins are the natives of the fictional Munchkin Country [i] in the Oz books [i] by L. Frank Baum [i] ... 

s. The storm cellar Storm cellar

Storm cellars are underground structures that are either located below buildings, or are built undergrou... 

 has also been used as a metaphor for seeking safety, as shown in the cartoon from 1894 at right.

A 1960s advertising campaign for the household cleaner Detergent

[i], or a mixture of compounds, intended to assist [[cleaning]... 

, Ajax Ajax cleanser

Ajax cleanser is a liquid or powdered industrial cleaner introduced by Colgate-Palmolive [i] in 1947.... 

, claimed the product "Cleans like a white tornado".

Tornadoes in dreams are sometimes said to be associated with fear, chaos Chaos

Chaos typically refers to unpredictability [i]. ... 

, and upheaval. It is alleged that the location where one is during a tornado dream, e.g. at home, can help to determine the meaning.

Motion pictures with a tornado theme


  • The Wizard of Oz, 1939.
  • Mr. and Mrs. Bridge Mr. and Mrs. Bridge

    Mr. & Mrs. Bridge [i] is a 1990 [i] is a Merchant Ivory Film [i] ... 

    , 1990.
  • , 1996.
  • , 1996.
  • Twister, 1996.
  • Atomic Twister , 2001.
  • The Day After Tomorrow The Day After Tomorrow

    The Day After Tomorrow is a 2004 [i] apocalyptic science-fiction [i] ... 

    , 2004.
  • , premiered on March 19, 2006.
  • , 2005.

See also

  • Cyclone Cyclone

    In meteorology [i], a cyclone is the rotation of a volume of air around an area of low atmospheric pressure [i] ... 

  • Derecho
  • Downburst Downburst

    A downburst is a column of sinking air that is capable of producing damaging straight-line winds of ... 

  • Dust Devil Dust devil

    A dust devil or whirlwind is a rotating updraft, ranging from small to large .... 

  • Emergency Alert System Emergency Alert System

    [i] put into place in [[1994]... 

  • Fire whirl
  • Funnel cloud Funnel cloud

    A funnel cloud is a funnel [i]-shaped cloud [i] of condensed [i] water [i] droplets, associ ... 

  • Gustnado
  • History of tropical cyclone-spawned tornadoes
  • Landspout Landspout

    A landspout is a slang-term used by storm chaser [i]s for a tornado [i] not associated with the mesocyclone [i] ... 

  • List of F5 tornadoes
  • List of tornadoes and tornado outbreaks
  • List of tornado-related deaths at schools List of tornado-related deaths at schools

    These are all tornado [i]es that have resulted in student deaths at schools in the United States [i] fro ... 

  • Mesocyclone Mesocyclone

    A mesocyclone is a large area of vertically spiraling air, usually associated with a supercell thunderstorm [i] ... 

  • Multiple vortex tornado Multiple vortex tornado

    A multiple vortex tornado is a tornado [i] that contains several vortices rotating around and inside ... 

  • NLM Cityhopper Flight 431
  • Severe weather Severe weather

    Severe weather phenomena are weather [i] conditions that are hazardous.... 

  • Supercell Supercell

    A supercell is a severe thunderstorm [i] with a deep rotating updraft [i] . ... 

  • Tornado Alley Tornado Alley

    Tornado Alley is a colloquial term most often used in reference to the area of the United States [i] in ... 

  • Tornado records
  • Tornadoes of 2006
  • Waterspout Waterspout

    A waterspout is an intense columnar vortex that occurs over a body of water and is connected to a cumuli... 



References


Further reading

  • Thomas P. Grazulis . Significant Tornadoes 1680-1991, A Chronology and Analysis of Events. The Tornado Project of Environmental Films. ISBN 1-879362-00-7

External links


;General
  • ~ Animation from MSNBC Interactive
  • Free archive of more than 50,000 newspaper articles detailing tornadoes through out history.


;Regional prediction



;Research



;Images



;Safety and Preparedness



;Miscellaneous