High waves, strong rip currents cause swim bans at Lake Michigan beaches

CHICAGO (WLS) -- High waves, strong rip currents and water quality concerns led to swim bans and beach hazard warnings Friday from southeast Wisconsin all the way to northern Indiana, the National Weather Service said.

Wave heights reached 4 to 7 feet, and strong rip currents and structural currents created dangerous conditions for swimmers along Lake Michigan. ABC7 Meteorologist Tracy Butler said the waves were caused by east winds reaching 15-25 mph.

Rip currents are powerful channels of water that flow quickly away from shore, occurring at low spots or breaks in sandbars, which can pull people into deep water. Structural currents form along piers where currents and waves flow into a structure, which can sweep people into deep water along the structure, the National Weather Service said.

A swim ban was issued for almost all of Chicago's beaches, the Chicago Parks Department said.

The only beaches not affect by the ban are 63rd Street, Calumet, Humboldt, Oakwood and Rainbow beaches. Those beaches are still dangerous to swimmers; a swim advisory has been issued for 63rd Street, Calumet, Oakwood and Rainbow beaches, due to rough surf and water quality. Humboldt Beach is the only beach in Chicago with no restrictions Friday.