Ice balls
Ice balls
Ice balls on Lake Michigan are currently forming along the shoreline near Traverse City.

In this video, shot on December 29, 2015, ice boulders are seen clanking against one another along the shores of Lake Michigan. What are they? Where did they come from?

This curious ice phenomenon doesn't happen often, so when it does, it's something to celebrate and take note of.

Ice balls start out life as a small chunk of ice in the water. The small chunk of ice grows by thin measures as it tumbles in the waves.

Ice boulders can only form when the air is cold enough for the water to instantly freeze and the lake is cold, but not too cold.

A stiff breeze helps to churn things up.

When a face of the ice boulder is hit with the water from a wave, it freezes in the cold air, getting just a bit larger in size.

After hours of tumbling, what started out as a small chunk of ice can grow to the big balls you see in the videos above and below.
Ice balls