Dear Tom,
Why don’t hurricanes form near the equator?
Aaditya Rawal, Prairie Grove, Ill.
Dear Aaditya,
Three ingredients are needed for hurricane formation: warm ocean water (80(degrees)-plus), light winds aloft and a sufficiently strong Coriolis effect–an apparent deflective force caused by the Earth’s rotation that imparts spin or “vorticity” to a developing storm. While warm water and light winds are in abundance near the equator, the Coriolis force is not. It is non-existent at the equator and only becomes strong enough to support hurricane formation at a distance of between 5 and 10 degrees of latitude from the equator. This is why a country like Panama, lying between 8 to 9 degrees north latitude, and coastal areas of Columbia and Venezuela at 10 degrees north latitude are rarely affected by hurricanes.
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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.
