Chicago (CBS) — A 16-year-old boy was rescued from the water and another boy is still missing from Lake Michigan off the coast of Waukegan, officials say.

Just after 4:30 p.m. Friday, the Waukegan Fire Department responded to a call for a person who had slipped off a pier into Lake Michigan at Waukegan Municipal Beach and another person who had jumped into the water to rescue the first.

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The teenager who originally fell in made it out of the water and was transported to Vista East Medical Center in Waukegan. His condition is unknown at this time.

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After about an hour and a half of searching the water, rescue divers were unable to locate the second teen. The operation was switched to involve sonar technicians.

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Divers are rescuers are waiting for the harsh weather conditions to move out of the area, so they can resume searching for the boy.