Winter Storm Delilah creates perfect condition for Lake Michigan ice balls to form

On top of bringing nearly a foot of snow to Wisconsin, Winter Storm Delilah also brought "ice balls" to Lake Michigan.

The giant spheres are a somewhat rare phenomenon.

RELATED: Lake Michigan's mesmerizing ice formations

Experts say they form on beaches when weather conditions are just right.

The temperatures must fall just below freezing along shallow beaches so slush can collect into round shapes and the waves sculpt the ice chunks into orbs.

Some of them are as big as three feet.

ALSO SEE: Winter Wonder: What is 'pancake ice' on Lake Michigan, how does it form?