A huge dusty whirlwind swept in Tempe in the us state of Arizona. A vortex spinning near the road, shot from the window of his car local news service brad Anderson.
“Dust devils” is known to have a diameter of from one to five meters. It is quite a common natural phenomenon in Arizona. In most cases, they pose no threat to people, but bigger “devils” can be devastating.
Vortex motion of the air occur at the earth’s surface in cloudy weather, usually hot, with strong heating of surfaces by sunlight. A vortex is formed when cold air abruptly hits the ground and rises in the form of warm air. Thrombus height from several meters up to 20 raises from the surface of the earth, sand, dust, stones and could carry them over long distances.