(WBBM Newsradio/CBS) — If you’ve got big icicles on your house, they could be the tip of an iceberg-size problem.

WBBM’s Steve Miller reports.

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“An icicle is one of the first signs of an ice dam.  And bigger the icicle, the greater the threat of an ice dam,” says Joe Palumbo, owner of Ice Dam Guys, based in Minneapolis.

This is an example of icicles and ice damming. (courtesy: IceDamGuys.com)

He’s sent crews to Chicago — right now there are 15 here — because that’s where the problem is. Ice damming occurs when ice builds up along a home; it can end up sending water inside.

He’s had thousands of calls from Chicago so far.

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“As far as voicemails, I can just tell you we’ve got about 300 we haven’t listened to yet,” he says.

According to Palumbo, the calls say basically the same thing: “My roof is leaking.  I have water in my kitchen, my living room, water coming through my windows.”

Palumbo says he does not recommend throwing those hockey-puck-sized ice melts on your roof.

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“We call them beer can coolers because most of the ice dams we remove have these perfect holes in them where you could just set a can of beer.”