A tornado is a violent, rotating column of air which is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. The most intense of all atmospheric phenomena, tornadoes come in many shapes and sizes but are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and dust.

Most tornadoes have wind speeds between 40 mph (64 km/h) and 110 mph (177 km/h), are approximately 250 feet (75 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 a mile (1.6 km) across, and stay on the ground for dozens of miles (more than 100 km).

Various types of tornadoes include the landspout, multiple vortex tornado, and waterspout. Waterspouts have similar characteristics to tornadoes, characterized by a spiraling funnel-shaped wind current that form over bodies of water, connecting to large cumulus and thunderstorm clouds. Waterspouts are generally classified as non-supercellular tornadoes that develop over bodies of water. These spiraling columns of air frequently develop in tropical areas close to the equator, and are less common at high latitudes.

Other tornado-like phenomena which exist in nature include the gustnado, dust devil, fire whirls, and steam devil.

Tornadoes have been observed on every continent except Antarctica. However, the vast majority of tornadoes in the world occur in the Tornado Alley region of the United States, although they can occur nearly anywhere in North America. They also occasionally occur in south-central and eastern Asia, the Philippines, east-central South America, Southern Africa, northwestern and southeast Europe, western and southeastern Australia, and New Zealand.

Tornadoes can be detected before or as they occur through the use of Pulse-Doppler radar 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 rates tornadoes by damage caused, and has been replaced in some countries by the updated Enhanced Fujita Scale. 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. The similar TORRO scale ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes.

A tornado outbreak sequence (or extended tornado outbreak) is a period of continuous or near continuous high tornado activity consisting of a series of tornado outbreaks over multiple days where there are very little or no days with a lack of tornado outbreaks. Major tornado outbreak sequences occurred in the United States in May 1917, 1930, 1949, and 2003. Another exceptional outbreak sequence apparently occurred during mid to late May 1896. Tornado outbreak sequences tend to dominate the tornado statistics for a year and often cause a spike in tornado numbers for the entire year. Read more ...

Tornado Alley is a loosely defined area of the central United States where tornadoes are most frequent. Although the official boundaries of Tornado Alley are not clearly defined, the main alley extends from northern Texas, through Oklahoma, Kansas, Nebraska, Iowa, South Dakota, Minnesota, Wisconsin, Illinois, Indiana, Missouri, Arkansas, North Dakota, Montana, and Ohio. Research suggests that the main alley may be shifting eastward away from the Great Plains, and that tornadoes are also becoming more frequent in the northern parts of Tornado Alley where it reaches the Canadian prairies.

Lightning Tornado

Lenticular Cloud

Tornado Family

A tornado family is a series of tornadoes spawned by the same supercell thunderstorm. These families form a line of successive or parallel tornado paths and can cover a short span or a vast distance. Tornado families are sometimes mistaken as a single continuous tornado, especially prior to the 1970s. Sometimes the tornado tracks can overlap and expert analysis is necessary to determine whether or not damage was created by a family or a single tornado. In some cases, such as the Hesston-Goessel, Kansas tornadoes of March 1990, different tornadoes of a tornado family merge, making discerning whether an event was continuous or not more difficult.

Space Tornado

A space tornado is a solar windstorm and is exponentially larger and more powerful than conventional tornadoes on Earth. They are also thought to produce the aurora borealis phenomenon. Tornadoes on Earth are formed by the atmosphere and sometimes having precipitation, while space tornadoes are formed by magnetic fields and with plasma.

Space tornadoes are made up of plasmas, consisting of extremely hot ionized gases that rotate at extremely high speeds, some recorded at over 1,000,000 miles per hour (1,600,000 km/h). Within its funnel, they also generate strong electrical currents of about 100,000 amperes. Power transformers and other man made constructs are susceptible to damage from space tornadoes. Read more



In the News ...

More than 30 tornadoes reportedly struck several states as severe weather swept across the South, leaving at least 7 dead so far   CNN - January 13, 2023
At least seven people, including a child, were killed as severe storms swept across the South, where ferocious winds sent residents running for cover, blew roofs off homes and knocked out power to thousands. Drone Footage From Selma, Alabama, Reveals Extent Of Tornado Damage

March saw more tornadoes in the US than any March on record   CNN - April 1, 2022

It's the second year in a row the country has endured a record number of tornadoes in March, solidifying a trend toward more severe weather earlier in the year and raising questions among scientists, who've historically seen such weather peak from April to early June. Meanwhile, more severe storms happening farther east in the country could mean more disastrous and deadly tornado outbreaks are possible.

Powerful tornadoes are relatively rare in the New Orleans area: Is global warming changing that?   PhysOrg - March 24, 2022

The powerful tornado that claimed one life and caused widespread damage as it roared through the New Orleans area Tuesday was one of the region's strongest in history and one of more than 100 tornadoes to strike in the past four decades.

Rare sight in Estelline, South Dakota - tornado spinning clockwise   KOTA TV - September 11, 2019

Only about 1 percent of tornadoes that hit the northern hemisphere rotate in a clockwise direction. This is significant because only about 1 percent of tornadoes that hit the northern hemisphere rotate in a clockwise direction.

What we know about tornadoes and climate change   CBS - March 6, 2019
The deadliest tornado to hit the U.S. in six years touched down in Alabama Sunday with winds of 170 mph and a path of 27 miles. It killed 23 people and was part of an early severe weather outbreak with 50 preliminary reports of tornadoes. At least 17 have been confirmed. But while some were quick to point to climate change as a cause of the tornado outbreak, current science isn't definitive about how much climate change influences tornadoes.