– What causes tornadoes to spin, and what causes them to stop spinning when they end?

Question

I know that (simplified) tornadoes form horizontally in a supercell due to opposing winds meeting, and it becomes a tornado when the rotating air goes vertical, but what sustains that rotation once the tornado is on the ground?

And then, once it’s on the ground, what causes it to eventually stop?

In: 1

Answer 1

Conservation of angular momentum, for one thing. Some research within the past 10 years or so has suggested this existence of something called a streamwise vorticity current, in which small whirlwinds are constantly moving into and merging with the tornado. At some point, rain-cooled air from another parts of the storm cuts off the circulation.