The following research is on the subject of the tornado. A tornado is a storm that moves rapidly and leaves considerable destruction in its wake. This meteorological event happens several times each year in the continental United States, and the cost in life and property is usually high. The tornado is the msot violent weather phenomenon. The wind speed is greater than that in the worst tropical cyclone. The most affected American states are Texas, Oklahoma, Kansas, Arkansas and Iowa. In no other region of the world are the conditions so favorable to the formation of tornadoes, nor are they as frequent when they do occur. They usually occur in the spring and summer, accompanied by thunderstorms.
Tornadoes are revolving storms which turn counterclockwise in the Northern Hemisphere. They have a small diameter and a rapidly rising column of air at the center. They are also barometric depressions that resemble tropical cyclones. However, they are much smaller, have a shorter life, and have much steeper gradients. The tornado begins when a funnel-shaped cloud develops in a low, heavy Cumulonimbus and extends toward the earth. This funnel rises and falls, turning in various directions. At the point at which it reaches the earth, there is almost total destruction accompanied by a deafening roar and semi-darkness. Where it fails to reach the earth, there is very little damage. Winds near the center are estimated at 200 to 500 miles per hour, and the updraft at the center also reaches very high speeds. Tornados are associated with the stongest natural winds that occur near the surface of the earth. The funnel always develops in association with the lower portion of an exceptionally violent thunderstorm. The storm passage may be preceeded and followed by heavy rain or hail, although some torndoes have been recorded with no form of precipitation in the area at all.
The lower part of the tornado is often surrounded...