Sometimes on a warm, sunny day, without much wind, you might be treated to a dust devil.

Whirlwinds, dust devils, and smoke devils are all variations of the same thing.

They look little like tornadoes, except that they are a lot less violent and a lot less dangerous.

It starts on a warm, sunny day. The sun is heating the ground and, somewhere, a hot spot forms.

WDAY logo
listen live
watch live

This hot air expands and it starts to rise, forming a small area of low pressure. and from all around, air will try to move in to balance that pressure difference.

But any slight disruption like a gentle breeze in the day will cause the incoming air to be slightly disrupted. and that disrupted motion is amplified more by more air coming in.

And pretty soon you have a rotating column of rising air: a vortex. Whirlwinds are invisible unless debris such as leaves or dust or smoke in the air makes it visible.

A similar vortex can be made by letting out the water in the bath.

And no, the rotation of the Earth has nothing to do with the direction of spin of these small vortices.

Dust devils and bathtub tornadoes can rotate either direction.