"What is that sand tornado thing I saw?"This was a legitimate question someone asked me recently after we posted a video of a tall, spinning column of wind that was full of dust and dirt. It was shot by one of our AZ Family employees in Tempe near I-10 and Elliot last weekend.First off, it may look like a tornado, but it's not. It's a dust devil.
[RELATED: Crazy dust devil in Tempe]They don't form from thunderstorms like tornadoes do. Dust devils typically develop under clear and calm conditions, from the ground up. The sun can heat up one area of the ground faster than other areas. Hot air rises from that spot, pressure lowers and the air around it begins to spin. This column stretches upward, and the spinning motion gets stronger. Winds increase, and the swirling air can pick up dust and dirt.Most dust devils are weak, but they can produce winds that exceed 80 mph and cause minor damage like an EF0 or EF1 tornado would. They can cover very small areas, at only 10 feet wide, or expand to about 100 feet. Either way, pilots are taught to avoid dust devils, as are skydivers.We see them quite regularly in the Valley when the weather gets dry and very warm. On a drive from Phoenix to Tucson, you might see dozens of them.While 'dust devil' is the name you hear the most, some in California call them 'sand augers' or 'dust whirls'. In Australia, they’re called 'willy-willies'. In the Middle East, where dust devils are even more impressive than Arizona, the whirlwinds are called a name which is a derivative of the word for “genie” or “spirit.”Dust devils are pretty much found around the globe. They're even found on Mars. They were first photographed by the Viking probe in the 1970s, and we've had closer looks since from Mars Pathfinder and the Spirit Rover.
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