CHICAGO (CBS) — The National Weather Service warned lakefront visitors Thursday that swimming conditions are going to be dangerous in Lake Michigan, due to high waves and rip currents.

WBBM Newsradio’s Mike Krauser reports the National Weather Service has issued a beach hazard statement through 5 a.m. Friday, as winds out of the northeast bring waves in the range of 3 feet to 6 feet high, all along the Illinois and northwest Indiana shoreline.

The forecast calls for conditions to build throughout the day, with dangerous pounding waves, and potentially life-threatening rip currents.

Rip currents don’t pull swimmers under the water, but rather away from shore. Swimmers can drown when they panic and try to swim toward shore against the current, and become exhausted.

There’s also a warning of strong structural currents, which form along piers and breakwalls. Even strong swimmers can get in trouble in conditions like those forecast for Thursday.

Even though Chicago’s official swimming season is over at its beaches – and Park District rules prohibit swimming when lifeguards are off-duty – many people who visit the lakefront venture into the lake anyway when there’s no one to keep an eye on swimmers.