Dear Tom,
I like to fish on the Fox River when it’s raining because it seems as if the rain calms the waves, even when it is windy. Can you explain this?
Jerry Misic
Dear Jerry,
It’s true: Rain calms choppy water. Here is how it works: When waves are in progress, they are transferring energy horizontally through the water in an orderly fashion. The motions of water particles are organized and rhythmic as waves move through, and the waves are moving along in the same direction as the wind (which adds more energy to existing waves).
When a raindrop strikes the water’s surface, it randomly creates a splash and then an eddy. Multiply this random effect by millions of raindrops striking the river, and the addition of all that random energy disrupts and dissipates the orderly wave train.
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Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN-TV News at noon and 9 p.m.
Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or asktomwhy@wgntv.com (Mail volume precludes personal response.)
WGN-TV meteorologists Steve Kahn, Richard Koeneman and Paul Dailey plus weather producer Bill Snyder contribute to this page.
