Dust Devils
photo taken from ziplink.net
Dust Devils are strong, long-lived whirlwinds ranging from small to over 10 meters wide and over 1000 meters tall. They are usually harmless but some can be large enough to threaten humans and property. They form when hot air near the surface rises quickly through a smaller pocket of cooler air pressure that is above it. Then, the air begins to rotate if the conditions are right. As the air rises, the hot air is stretched vertically which intensifies the spinning effect. As the hot air rises, it cools, losing its buoyancy. The cool air is displaced and descends outside the vortex’s core. The cool air returns and acts as a balance against the spinning hot air outer wall and keeps the system stable.
Dust Devils have also occurred on the planet Mars. To learn more about Dust Devils, visit Wikipedia’s article, Dust devil.
