CHICAGO (CBS) — It’s hot, it’s Memorial Day weekend. In Chicago, that means thousands of people heading to the beach.

But before you go: a warning.

Fifteen-year-old Lexie Adu was cooling off at a Rogers Park beach Thursday night when she drowned.

Her father says the 15-year-old was dangling her feet in the water when a wave swept her into the water. Her body was found Friday morning.

Drowning is the leading accidental cause of death for children up to four years of age. For children 14 and under, it’s the second leading cause of accidental death.

That’s why it’s important for parents and children alike to be cautious as we begin another swimming season.

With its postcard-worthy sunrises, picturesque boats and the occasional hula hoop performer, there’s seemingly no better   place to be than along Chicago’s miles of lakefront.

But as surely as it’s beautiful, it’s dangerous.

Lexie and her friends went in the water in an area where no lifeguards were on duty. That’s how it was Friday in Evanston, where these young boys for a while tried to pretend they were guarding the beach.

But they didn’t need guards because the 62 degree water had them thinking twice about going in.

But as the temperatures rise more and more, people will be tempted to cool off by taking a dip. Lifeguards say people have to have a healthy respect of the water.

According to the U.S. Lifeguard Association, your chance of drowning at a guarded beach is about one in 18 million.

But you are five times more likely to drown at an unguarded beach.