Formation of Tornadoes

¶ … formation of a tornado; the composition, causes, kinds and magnitude of destruction this natural calamity is capable to bring about. Tornado, a mysterious and violently destructive windstorm, is a funnel-shaped cloud extending towards the ground with a dark cumulonimbus mass on its end facing the ground. The funnel twists about into a mad oscillation of 200-300 miles per hour and is capable of causing great destruction where it meets civilization. This paper unlocks the mysteries of how a tornado is formed and unveils a violent aspect of Mother Nature.

TORNADO Before we can understand how a tornado is formed, it is important that we discover and visualize the structure and mechanism of such a gigantic body. A tornado is a rotating column of air with a width of a few yards to more than a mile which spins at destructive high speeds accompanied by a conical downward extension of a cumulonimbus mass of cloud. A cumulonimbus cloud is a massively dense, vertically developed accumulation with a faintly hazy outline extending great heights.

It usually produces heavy rains, thunderstorms, or hailstorms. The diameter of a tornado varies between a few feet to a mile. The range of a tornado can extend from less than a mile to several hundred miles. Its direction is dependent upon that of the prevailing wind. Generally, tornadoes travel in a northeast direction at a speed ranging 20-60 m.p.h. The scale that measures the severity of a tornado is called the Fujita Scale.

The Fujita or F-scale measures the severity of a tornado by the damage it causes. Wurman, a meteorologist of high stature, has constructed a mobile radio weather forecaster known as Doppler on wheels to study tornadoes more closely, his research and efforts will help in providing better forecasts of tornadoes. "Warnings usually only happen with a few minutes of lead time," he says. "In five minutes, you might not get your kids out of the yard and into the basement."(Kirstein Weir, 2004).

Usually tornadoes are accompanied by thunder, lightning, hurricane and a loud "freight train like" noise. However, in comparison with cyclones and hurricanes, tornadoes cover a smaller area, are short-lived but can be just as violent and destructive. Even though tornadoes have occurred on every continent except for Antarctica which lacks weather conditions viable of causing it, they are most frequented in the continental United States. Tornadoes typically form over the central and southern plains, the Ohio Valley and Gulf States.

The area where tornadoes occur most frequently is called the Tornado Alley. The Tornado alley encompasses N. Central Texas north to the Dakotas. The peak frequency, which is the region where tornadoes frequent most, is located in Oklahoma. Tornadoes that occur over water are called waterspouts. The awe striking thing about tornado is that this huge swirling beast of a storm appears to have a mind of its own. In order to understand the mechanism of a tornado, observers and meteorologists compare them with a bathtub whirlpool.

When the water drains from a bathtub a whirlpool is formed. This whirlpool is also known as vortex. The vortex is formed because of the downward pull the drain creates in the water body. A downward flow of water begins to rotate, and as the rotation speeds, a vortex is formed. There are many explanations as to why the water should start rotating. It is a consequence of "suction" created by the drain. The water particles accelerate towards the point of suction.

Because of the exceeding momentum every particle is moving towards the same suction point. This sets off a deflection due to which a spiraling path to the point of suction takes course. As this spiral pathway takes its course, it tends to influence all the other particles. In this way a very strong spiraling tendency is created, due to shooting momentum. This finally makes a vortex. In a tornado, the same sort of thing happens, except with air instead of water. FORMATION OF A TORNADO.

Tornadoes are most often generated by giant size thunderstorms. Typically a thunderstorm cloud can accumulate a huge amount of energy. Under certain conditions, this energy creates an upward pull in the cloud. As clouds form due to the condensation of water vapor in the air. This change in water's physical state releases heat-which is a form of energy. Thus greater condensation accounts for massive energy in a thunderstorm. According to Encyclopedia Britannica: "For every gram of water condensed, about 600 calories of heat are made available.

When the water freezes in the upper parts of the cloud, another 80 calories of heat per gram of water are released. This energy goes to increase the temperature of the updraft and, in part, is converted to kinetic energy of upward and downward air movement. If the quantity of water that is condensed in and subsequently precipitated from a cloud is known, then the total energy of a thunderstorm can be calculated.

In an average thunderstorm, the energy released amounts to about 10,000,000 kilowatt-hours, which is equivalent to a 20-kiloton nuclear warhead. A large, severe thunderstorm might be 10 to 100 times more energetic. " Thunderstorms of such a massive gait are known as "supercells." (Wollard, 1999) These colossal, powerful and highly organized storms when get warm and moist air along the ground rush upwards meeting cooler drier air. As this rising warm air cools, its moisture condenses, resulting into a massive thundercloud, sometimes it grows to as much as 50,000 feet in vertical length.

At different levels of the atmosphere, varying winds feed the updraft and cause the formation of a funnel-shape, characteristic of a tornado. The updraft in supercell thunderstorms is very strong (Wollard, 1999). If they are strong enough, a vortex, similar to the one water forms in a sink, is formed. An air vortex under such a thunderstorm cloud is called tornado. A tornado extends out of a thundercloud as a huge, swirling.