What Causes Tornadoes

Tornadoes, also referred to as twisters or thunderstorms, are violent rotating columns of air, that extend from the ground to cumulonimbus clouds. Though these destructive thunderstorms come in various shapes and sizes, the shape most often observed is that of a funnel - broad at the highest point and narrow at the base.

What Causes Tornadoes to Form?

Conditions suitable for the formation of a tornado develop when varying temperatures and humidity come together and form thunderclouds. This refers to the presence of warm and moist condition in the lower atmosphere, and cold and dry conditions in the upper atmosphere. The place where these varying masses of air meet is known as the dry-line. These conditions suitable for the formation of a tornado are most often observed just before a low pressure system develops.

Once the ideal conditions occur, the warm air tries to rise in the atmosphere, while the cold air blocks it. This makes the air in between to start rotating horizontally. In the meanwhile, the land is heated by the sun, and hence, the air near the ground becomes warmer and starts to rise. Continuous fueling by the heat energy from the Sun ensures that the warm air has an upper hand over its cold counterpart. As a result of this, the cold air at the top starts sinking, and the warm air below starts rising upwards in spinning motion. As the amount of warm air increases, the formation gets taller and more intense. The intensity of these devastating tornadoes is such, that it can clear off anything that comes in its path.

The United States Perspective

In the United States, the cooler polar air masses and the warm tropical air masses come together to form a tornado. This is caused as the warm, wet winds from the Gulf of Mexico move towards the north, and the cold, dry winds from Canada move towards the south. Tornadoes caused during the late winter or early spring, are fueled by the strong, frontal systems which are occur in the Central States, and move towards the east. In the High Plains of the United States, thunderstorms are caused when the air in the lower atmosphere is pushed up along the higher terrain.

Facts About Tornadoes

Approximately 95% of these tornadoes rotate in counter-clockwise direction. On an average, the speed at which these huge columns of air rotate ranges between 40 mph to 110 mph. The height of the tornado and its speed have a direct relationship, which means taller the tornado, faster will be its rotation speed. At times, these monsters can grow to a height of 10 miles in the air, and thus, cause wide-spread destruction in the vicinity. These tornado facts make them one of the most dreaded natural disasters we can face.

The United States experiences the most number of tornadoes in the world, followed by the Indian subcontinent. Some of the famous tornadoes which created havoc in the United States include the Waco Tornado (1953) and the New Richmond Tornado (1899). The destruction caused by these tornadoes in itself can give you a rough idea of how dangerous they can be.