Dust devils are something usually seen in the distance on a hot day. I remember as a boy having to sometimes re-rake a hayfield prior to baling when a dust devil would come through to rip apart the cured windrows. Today, I filmed one close-up that came down an oil field road, spinning dust into the air.
Dust devils form when hot air near the ground ascends through cooler, low pressure air above it. Breezes can set the column of rising air to spinning, and once that starts, cooler air is sucked into the vortex and you’ve got a spinning updraft not unlike a tornado, though formed differently and on a much smaller scale. Most dust devils are small – about three feet across – with winds of about 45 miles per hour. That’s enough to stir up dust, but seldom enough to cause damage.
On rare occasions, dust devils can get much larger and last for tens of minutes. Some have been known to produce winds of 75 mph, approaching the power of an EF0 tornado.
The one I filmed today was average-sized, and interestingly, came almost directly to me. It veered into the grass at the last second, but the whirling wind was strong enough to blow your hat off.
It was an interesting experience on another day of record-breaking temperatures. Time for that stuff to end!