Hi Tom,
Is it true that each snowflake is unique? How can that be?
Margie Timmins, Gurnee, Ill.
Dear Margie,
When we think of a snowflake, we picture a hexagonal dendrite–a lacy, branching, six-sided ice crystal. But snowflakes come in other shapes including needles, hollow columns, and any variety of deformed hexagons. Formation is caused when water molecules weakly bond together when frozen, usually hexagonally. Shape and size are largely dependant on temperature, humidity, wind flow, and the constantly changing environment through which the snowflake falls.
As a result, no two flakes are exactly alike at the molecular level. The number of molecules, spin of electrons, and isotopes make the possibilities nearly infinite. Further variations are possible since a snowflake is three dimensional. No doubt two flakes have looked alike, but so many factors make identical snowflakes improbable.
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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 Dennis Haller, Richard Koeneman and weather producer Bill Snyder contribute to this page.
