Microburst!

Contributed by
Sep 20, 2015
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A microburst might sound like some astronomical minicatastrophe, but it’s actually a much more terrestrial event: A sudden accelerating downdraft of wind from a cloud that can, at times, be quite violent.

Some are dry, with just air descending at high speed, while some are wet, loaded with water. Photographer Bryan Snider caught the latter when he was taking time-lapse footage of a thunderstorm over Tucson, Arizona, on Aug. 8:

You can see the rain falling, then at about 00:11 you can see the microburst develop and drop. A second one happens just moments later, too. It’s fascinating to see it hit the ground and blow outwards in a circle. The position of the Sun was perfect to illuminate just the bottom of the event. (Note: After I wrote this, but before it went live, I found that a webcam at Kitt Peak National Observatory caught the same microburst.)

This one didn’t look too violent, despite the scale. But microbursts can be; one that let loose in Montana in 1998 knocked down trees like they were twigs. Even less powerful ones can be a danger to aircraft, and they’re difficult to predict.

I’ve never seen an actual microburst, though I did once see a series of downdrafts from clouds forming beautiful fingers as they descended, one after another in a row. It was mesmerizing, and interestingly enough I asked some meteorologists to help me identify them, but we came up empty.

It’s not unusual for astronomers to be interested in meteorology, and meteorologists to be interested in astronomy. After all, we both look up for a living, and there’s always something amazing waiting to be seen in the sky.

Tip o' the umbrella to Henry NL.