SAUGATUCK, MI - On Sunday, Feb. 16, images of a fascinating winter phenomenon on the Great Lakes were shared by the National Weather Service’s Grand Rapids office.

On Saugatuck’s Oval Beach, along Lake Michigan, NWS snapped photos of “ice volcanoes” erupting along the shore.

The conical structures form above sand bars and reefs near the lakeshore as ice shelves build during cold periods. After the ice shelf has built out, waves continue to travel underneath the ice and are forced up through cracks and previously-formed cones.