EVANSTON, Ill. (CBS) — A shifting shoreline is causing big concerns in Evanston.

Massive boulders are designed to protect the lakefront but they’ve become a popular place to hang out.

CBS 2’s Vince Gerasole reported Thursday evening on why people are being told to stay away.

There is something mesmerizing about the waves crashing against Evanston’s lakefront, but for this report, also pay attention to the rock wall that’s supposed to keep Lake Michgan’s waters from washing away the Shorefront Park.

“The big rocks up there are being undermined by the wave action,” said Evanston Public Works Director David Stoneback.

No matter how solid the large boulders may look, many are coming loose because of the rising lake level and the waves now washing over them.

Stoneback pointed out the problem.

“You can see all the ice on this rock where it’s obviously come over,” Stoneback said. “Then when it washes back into the lake and it undermines all the soil under the rock.”

The rock wall was put in place in 1988, the last time similarly high and turbulent waves threatened Evanston’s shoreline.

And though sometimes maligned, the rocks have also become an attraction. People hang out and sometimes paint them, even pose for wedding pictures, and that stands to be a problem.

“If you are standing up there it could collapse at any point,” Stoneback said.

The Army Corps of Engenieers has helped Evanston evaluate weak spots; shoring up the land and building building higher barriers are suggested.

A several million dollar project funded through a federal grant.

“Part of it will be putting the rocks back where they should be once we get them stabilized,” Stoneback said.

But until repairs can start when the weather breaks, the city is warning park goers to stay off the rocks.