PAUSE & REFLECT NEWS: Tornado Formation and Destruction

by Ryan G. Banister

In modern literature, the term "tornado" is used in relation to two different physical processes, which have some similarities.

One process is caused by the uprising of air from the heated surface of the Earth. A moderate circulation of air at the periphery transforms into a strong rotation in the middle creating a helical flow directed upward. With this helical flow, the air entrains the dust from the ground. This type of tornado is referred to as a "dust devil."

The other process, born from a "tornadic" cumulonimbus cloud or a large cumulus cloud, is quite different. This united swirling flow, the more dangerous form of a tornado, touches the Earth's surface in the form of a long, narrow funnel. The air inside the funnel rotates with a high speed, which sometimes approaches the speed of sound.

The thunderstorm cloud, which is part of a small tropical hurricane, has a so-called "eye." This cloud has a spiral structure. If the whirlwind cloud has a large size, it will appear to be very similar to a cyclone. Cyclones can often produce tornadoes.

A circular cavity is formed in the center of the funnel by rotating clouds. The pressure inside of a tornado is very low, and when the cavity touches a building with windows tightly shut, the building almost explodes from inside and the walls can can be thrust outward. Tornadoes have such an incredible force that they can throw tractor trailers across large distances. However, they can have quite selective effects and have been seen removing a roof from a house, leaving many objects inside the house intact. They can also expose the bottom of lakes, sucking up the water contained therein.

Source:

Merkulov, Vladimir I. Amazing Hydromechanics. Bloomington, IN: AuthorHouse, 2012. Print