SAULT STE. MARIE, Mich. (AP) — Authorities are warning that ice on some of the Great Lakes and waterways in Michigan’s Upper and Lower peninsulas could be unsafe.

The U.S. Coast Guard says caution should be taken when venturing onto ice on Lake Superior, northern parts of Lake Michigan and Lake Huron, and the St. Marys River.

Sector Sault Ste. Marie commander Capt. Steve Teschendorf says snow forecast this weekend in some areas could give people the false impression that ice is thick enough to travel on.

The Coast Guard says ice is unpredictable and the thickness can vary, even in small areas.