Dear Tom,
During the storms that blew through the Chicago area in October, we saw what appeared to be colored lightning flashes while winds were raging. What was it?
Gary Markis, Chicago
Dear Gary,
You are referring to the evening of Oct. 2, when intense thunderstorms raked the Chicago area with 60-90 m.p.h. wind gusts.
Bursts of light in hues of blue, green and red were not from lightning but from arcs of electricity from downed power lines and from lines making contact with fallen tree limbs. Low clouds reflected light from those arcs, which, given the night’s incredible winds, were taking place all across Chicagoland.
Aluminum and copper conductors are used in power lines. High winds can cause the lines to slap together, overheating and producing a colorized burning current similar to the sparks created during arc welding.
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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.)
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