Not a good day for lake surfing. The shores of Lake Michigan look like they are being assaulted by floating boulders! No, these aren't rocks, but balls of ice. They form as small pieces of ice that grow in layers as water freezes against them, but due to the wave action of the lake, the chunks are tumbled about and the edges are smoothed off until they are round. This video was captured at Glen Arbor by Glen Arbor Artisans.
See an explanation on how these ice balls form from about a year ago. -Thanks, Terrence!