(CBS) – No question it has been freezing around here lately, cold enough to freeze some of those ponds and lakes around Chicago.

But just how safe is that ice? CBS 2’s Pamela Jones reports.

You can see the white, chunky frozen shoreline of Lake Michigan and smaller bodies of water look pretty solid when you’re standing on the shore.

But experts say beware.

Des Plaines Fire Lt. Michael Iorio took CBS 2 on Big Bend Lake to measure the thickness, a good sign of strength.

But he says even with a hard freeze, some areas that look rock solid could actually be weak enough to sink you.