Rethinking the rain

What falls on your head is not what you think it is.
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Rain over Elliott Bay, March 2009

What falls on your head is not what you think it is.

The Salish speakers of Puget Sound had many words for rain, but it turns out we ought to have a larger vocabulary about raindrops. I was reading a story about new research indicating that snowflakes aren't portrayed accurately on Christmas cards and the like. Turns out four-, five- and eight-sided flakes don't exist in nature. Snowflakes are six-sided. Of course, this being an El Nino year, it might be too mild for us Wetside lowlanders to do much research on this front this year.

But the article went on to mention that raindrops, something all of us know about, are in fact not "raindrop" shaped, despite the fact that even government mascots would have you believe it. The raindrop is often depicted on weather reports and charts as a kind of falling teardrop, rounded at the bottom and peaked on top, like a faucet drip.

But raindrops start out as little spheres, and change shape while falling. There's a very cool video of the process here, where droplets begin as spheres, flatten out as they fall, curl into a kind of parachute or balloon shape, then burst into a spray of droplets. So drops can have many different shapes in the course of a fall.

The shapes that drops take depend on the size of the drop and conditions like wind. Some are spherical, some are like pancakes, some like jellyfish. This makes sense to anyone who has been out in the various rains we have here: neat little spheres and raindrops don't begin to explain the variety of ways you can get wet from the sky. But trying to nail down the shape of rain is something most of us don't give much thought to.

University of Washington weather expert Cliff Mass says all this is old news. "The classic tear drop doesn't exist," he says. Following with this stunning revelation: "And Santa Claus isn't real either." I can accept the former, but am not ready to concede the latter.


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About the Authors & Contributors

Knute Berger

Knute Berger

Knute “Mossback” Berger is Crosscut's Editor-at-Large.