A driver on an Arizona freeway captured this impressive moment of a dust devil making its way into town. A dust devil is a strong, well-formed, and relatively long-lived whirlwind, ranging from small to large. Dust devils form as a swirling updraft under sunny conditions during fair weather, rarely coming close to the intensity of a tornado. Dust devils form when a pocket of hot air near the surface rises quickly through cooler air above it, forming an updraft. If conditions are just right, the updraft may begin to rotate. As the air rapidly rises, the column of hot air is stretched vertically, thereby moving mass closer to the axis of rotation, which causes intensification of the spinning effect.
Massive Dust Devil Spotted on Arizona Freeway