Friday, April 23, 2010

What is a Tornado?

Unusually violent weather is called a storm, and is always accompanied by high winds. Some of these winds have spiraling internal movements, and the revolving storms they produce are variously called tornadoes, whirlwinds, willy-willies, waterspouts and hurricanes.

Near the center of a tornado is an area of calm known as they eye of the storm. This is simply a hollow vortex formed by the spiraling of the air, rather like the center of a vortex of water going down a drain. Because of the suction in this low-pressure eye, houses collapse and roofs are carried off, corks are drawn from bottles, and window panes fall outward.

Around the edge of the funnel-shaped cloud of the tornado, which looks like an enormous spinning top and almost touches the ground, the wind may blow at 200 miles an hour. The storm belt, only a few thousand feet wide, travels at 25 to 40 miles an hour, to the accompaniment of a deafening roar.

A waterspout is a tornado at sea, sucking in water and carrying it in an upward spiral with the wind to the overhanging cloud. A ship entering a waterspout soon finds her bridge and rigging covered with insects and birds. They are exhausted by their struggle in the side of the waterspout they have just passed through and are seizing the chance to rest in the eye before being caught up in the fury of the other side.

Tornadoes occur in the middle latitudes of the earth.

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