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.

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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.

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ABC 7 Chicago Meteorologist Cheryl Scott explains what Lake Michigan's pancake ice is and how it forms.