How Tornadoes Are Formed
A tornado in general is a rotating column of air which is normally accompanied by a funnel-shaped downward extension of a cumulonimbus cloud (Cb), a type of cumulus cloud. It has a mass of several hundred yards in diameter and the narrow column of air rotates very fast and leaves enormous devastation in its route. A tornado whirls destructively usually at speeds of up to 300 miles per hour (480km).
The devastation created by tornadoes occurs because of the harsh violent winds and partly to the very low pressure. This sort of development has the effect of causing buildings to explode outwards because the pressure outside exceeds that of inside the building and although a tornado may affect an area only 100-160 meters across, the outcome is total destruction.
Tornadoes are often unpredictable in their manner and behavior and can lose contact with the ground or retrace their path routes. When a tornado moves out over to the sea, and once the tunnel has connected with the waves, a waterspout is developed. Basically, a waterspout is somewhat similar to a land tornado, it is funnel-shaped or a lesser whirlwind occurring over water and resulting in a whirling column of spray and mist.
A tornado develops around a center of very low pressure with high wind speeds blowing anticlockwise and with a violent downdraft. The common appearance of a tornado is of a funnel or a swirling snake-like column filled with cloud and it's usually no more than 140-160 meters across.
The exact manner in which tornadoes form is not fully acknowledged although it involves the interface of warm moist air with dry cooler air and an inversion of temperatures with some event acting as a trigger, and sometimes believed to be an intense cold front. These sort of conditions are found in several countries at mid to low latitudes, but particularly so in the mid-west of the Unites States.