Video from Arizona: Double dust devils

Impressive footage captured in the US state of Arizona sees two large dust devils in action. The diminutive tornadoes swept across the landscape on Friday.

Dust devils are small and relatively weak tornadoes. They often form in dry areas over a highly heated and dusty surface when air rises and begins to rotate.

In contrast to tornadoes, dust devils occur in calm and dry weather. They usually only reach a height of a few dozen metres and are usually much more harmless than tornadoes.