CHICAGO (CBS) — The Chicago Police Marine Unit has a word of warning for boaters and swimmers.

As WBBM Newsradio’s Steve Miller reports, police say the heat wave is creating some hazardous situations in Lake Michigan.

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LISTEN: WBBM Newsradio’s Steve Miller reports

“With this heat wave, we’re getting all kinds of calls – people in the water,” said Chicago Police Marine Unit Officer Michael Michalik.

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Michalik says Wednesday was a busy day for the Marine Unit, which he was expecting. He has been assigned to the Marine Unit for 12 years.

And the heat wave continues – with boaters flocking to the lake.

“Lake Michigan is not a small inland lake like the Chain O’Lakes, Fox Lake,” Michalik said. “The weather can change out there. The conditions can become very dangerous. You have to be alert and aware and have all the proper safety equipment on your vessel at all times.”

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As for swimmers, the Police Marine Unit says even the ones who think they’re pretty good have a challenge in Lake Michigan – a body of water vastly different than the calm swimming pools where most people learned to swim.