NASHVILLE, Tenn. (WKRN) – Severe weather season in the south brings the enhanced threat of tornadoes. And, while we have entered Hurricane season, tornadoes can happen any time of the year.

How do tornadoes form?

You have to start by looking at different levels of the atmosphere, particularly, in terms of the wind. In order for tornadoes to form, you need the wind speed, and wind direction to differ between the surface and the upper levels of the atmosphere. A factor referred to as “wind shear”.

The difference between the surface and upper level winds creates a rotating, horizontal column of air. When that column contacts the updraft of a thunderstorm (warm air rapidly rising within a storm), it will tilt vertically.

If conditions are right, a wall cloud will extend from the cloud base, and then that now-vertical column of air will extend out of the wall cloud. If it doesn’t reach the ground, it’s technically classified as a funnel cloud. However, if that column does reach the ground, it officially becomes a tornado.