Willy Willies sometimes occur on extremely hot and still days when the sun superheats the ground. This super-hot ground heats layers of air above that, which in turn heats other layers above that. Since hot air expands and is therefore less dense, it will rise through cooler and denser air quite rapidly.

Is a willy willy a tornado?

The willy-willy is now a “mini tornado” following “a path of destruction”. ... Mini tornadoes merely put the frighteners on tv journalists.

What causes dirt devils?

Dust devils form when hot air at the surface begins to rise rapidly with much cooler air above it and higher up into the atmosphere. The hot air then stretches and causes a spinning motion much like a tornado. ... Dust devils become visible when they form over barren terrain, tarmac, and desert-like terrain.