Dear Tom,
Is it ever too cold to snow?
Jennifer Ratkovich, Algonquin, Ill. & Kate Santine , Peoria, Ill.
Dear Jennifer and Kate,
The belief that it can ever be “too cold to snow” is as pervasive as it is incorrect. Let’s speak clearly on the subject: In the Earth’s atmosphere, it can never be too cold to snow. All that is necessary is water vapor in the air–and some is always present, even at very low temperatures–and a mechanism to chill the air below its saturation temperature.
The Antarctic environment satisfies both conditions, and the icecap is dramatic proof that snow falls there in frigid temperatures. Direct observation confirms it. Ice crystals and light snow have been observed at the South Pole Station with temperatures at -70(degrees)F. Even Chicago has simultaneously experienced snow and bitter cold. On Jan. 10,1982, 0.8″ of snow was observed at Midway Airport while the temperature was -15(degrees).
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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.
