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.
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 that exist in nature include the gustnado, dust devil, fire whirl, and steam devil.
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.
Most tornadoes take on the appearance of a narrow funnel, a few hundred yards (meters) across, with a small cloud of debris near the ground.
Although the condensation funnel may not extend all the way to the ground, if associated surface winds are greater than 40 mph (64 km/h), the circulation is considered a tornado.
A tornado with a nearly cylindrical profile and relative low height is sometimes referred to as a "stovepipe" tornado.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".For a vortex to be classified as a tornado, it must be in contact with both the ground and the cloud base.Waterspouts are characterized by a spiraling funnel-shaped wind current, connecting to a large cumulus or cumulonimbus cloud.They are generally classified as non-supercellular tornadoes that develop over bodies of water, but there is disagreement over whether to classify them as true tornadoes.Tornadoes may be obscured completely by rain or dust.These tornadoes are especially dangerous, as even experienced meteorologists might not see them. Small, relatively weak landspouts may be visible only as a small swirl of dust on the ground.This results in the formation of a visible funnel cloud or condensation funnel.There is some disagreement over the definition of a funnel cloud and a condensation funnel.Tornadoes occur most frequently in North America, particularly in central and southeastern regions of the United States colloquially known as tornado alley, 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 or debris balls, as well as through the efforts of storm spotters.There are several scales for rating the strength of tornadoes.