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What kinds of clouds form tornadoes?


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October 27, 2011 4:22PM

Technically, it's a process of multiple cloud levels. Tornadoes form from Funnel Clouds, which form from Wall Clouds, which form along the base of Cumulonimbus clouds. So you start with a Cumulonimbus cloud (also known as a thunderhead or thunderstorm cloud) and a wall cloud can form along the base it. A wall cloud is a lowered base of a storm that is rotating.

Attached to several wall clouds, especially in moist environments, is a tail cloud,which is just a band of clouds that resemble a tail. Most often the wall clouds' movement will be horizontal and in other clouds may be seen as moving in toward the wall cloud. There is also sometimes something called a collar cloud atop the wall cloud which is a band of clouds circling over it. Wall clouds will usually will slope inward, or toward the precipitation area.

From that wall cloud, a smaller lowering of rotation can occur, often in a funnel shape, known as a funnel cloud. If that funnel cloud reaches the ground, it's known as a tornado.