Dear Tom,
Are the huge icebergs and ice fields on Earth composed mostly of frozen salt water or are some of them fresh water?
Dora, Chicago
Dear Thelma,
All of the world’s ice that is formed from the accumulation of snowfall is fresh. It contains no salt. That includes mountain glaciers, the massive ice fields of Greenland and Antarctica, and the icebergs that break off from glaciers and icecaps and drift into the world?s oceans. None of that ice contains salt.
The source of all precipitation– rain and snow–is water that has evaporated into the atmosphere. However, evaporation takes only pure water into the air; all dissolved salts and minerals are left behind. As a consequence, rain and snow are salt-free.
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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.
WGN-TV meteorologists Steve Kahn, Richard Koeneman and Paul Dailey plus weather producer Bill Snyder contribute to this page.
