surface air or when its movement slows down, thereby using up all available hot air.

Certain conditions increase the likelihood of dust devil formation.
* Flat barren terrain, desert or tarmac: Flat conditions increase the likelihood of the hot-air "fuel" being a near constant. Dusty or sandy conditions will cause particles to become caught up in the vortex, making the dust devil easily visible, but are not necessary for the formation of the vortex.
* Clear skies or lightly cloudy conditions: The surface needs