Dear Tom,
How does the rain from a hurricane that has just come onto shore become fresh water and not have a high or even minimum salt content?
Suzie McGinn, Barrington
Dear Suzie,
Cloud and rain development in a hurricane occur the same way they do over land or sea, by the evaporation and lifting of water vapor into the atmosphere. This water vapor is pretty much pure water and nothing else, with the salt of sea water left behind. Therefore, as it condenses to clouds and then rain, it is fresh water. On the other hand, as the storm surge pushes inland with hurricane landfall, that water is almost exclusively sea water, physically driven inland from the ocean by the winds of a hurricane.
Some other effects possible with hurricanes are huge rainfall totals over a short time period–with little or no lightning.
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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.
