Dear Tom,
Why do clouds often hang around mountain peaks?
Thanks, Bob Miskimins
Dear Bob,
Clouds that hang around mountain peaks are called cloud caps, but the official name for it is a lenticular cloud. These clouds form when moist air moving with the prevailing wind flow runs into the mountain surface, and is forced upwards until it cools enough for condensation to occur causing the cloud to form around the mountain top.
As the air descends on the other side of the peak it warms, dissipating the cloud. Cloud caps will not form if the air is very dry, so their presence means that atmospheric moisture is increasing and that precipitation may be on the way.
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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.
