CHICAGO (CBS) – The Chicago Triathlon will switch to a duathlon as the swim portion was canceled due to dangerous conditions at Lake Michigan beaches, according to its website.

"Due to unfavorable swim conditions and a beach hazard issued by the City of Chicago, today's swim has been canceled."

The cancellation comes a day after four people were rescued at North Avenue Beach when their jet skis turned over. 

Over 6,000 athletes will take on the triathlon on Sunday.

But there's the 46-mile bike ride along DuSable Lake Shore Drive, a nearly 11-mile run in and around the museum campus.

The sprint distance race will start around 8 a.m.

Athletes will cross the finish line at Grant Park.