Hail And Tornadoes

1885 Words8 Pages
Hail and Tornadoes Description and Classification Tornadoes According to the Glossary of Meteorology, 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." Tornadoes occur all over the world, but are especially prevalent in the United States. Tornadoes usually have wind speeds between 40 and 110 mph, forward speeds approximately 30 mph, and are usually around 250 feet across. They generally travel only a few miles before dissipating. The word "tornado" comes from the Spanish or Portuguese verb tornar, meaning "to turn." Some common related slang terms include twister, whirlwind, wedge, funnel, willy-willy, or rope. Tornadoes are often also known as cyclones. It should be noted, however, that in certain parts of the world (notably Australia) a cyclone refers to what is more correctly known as a tropical cyclone, hurricane, or typhoon. Meteorologists also use the term cyclone to refer to other types of circular weather systems. To avoid confusion, use of the term "cyclone" on its own should therefore be avoided when describing a tornado. Characteristics Tornadoes are primarily made of (invisible) air, and only become visible when they contain debris and condensed moisture. When this happens, they usually appear as dark and rope- or wedge-shaped. Tornadoes will occasionally softly "glow" due to lightning discharges in or near them. The sound of a tornado varies widely. It is actually a combination of many different sounds, usually created by rushing air and damage to ground structures. Most commonly, the sound of a tornado is described as a whooshing roar. The temperature is generally lower inside a tornado. The pressure is usually lower as well, due to the Bernoulli Effect. (The
Open Document