The shores of Good Harbor Bay on Lake Michigan are being invaded by a strange phenomenon: Giant ice boulders.
Hundreds of basketball-sized ice boulders weighing up to 75 pounds have been piling up on the lake for the last week or so.
It's not uncommon, but it's definitely unusual, according to Tom Ulrich, Deputy Superintendent from the Sleeping Bear Dunes National Lakeshore.
"It's not that it never happens and this is a once in a decade thing," he told UpNorthLive.com. "It happens more often than that, but these are very large and got bigger than they normally get."
The giant frozen balls are created when ice chunks form along the shore, get churned back and forth by the waves and grow slowly in the just-below-freezing water, a process that also helps to smooth the boulders, according to Lisa Myers, Sleeping Bear National Lakeshore's chief of interpretation and visitor services.
"The Great Lakes create their own weather," Myers told the Los Angeles Times, adding that the boulders compete with ice caves and large icicles for the park's most interesting ice creations.
Ledia Olmstead is credited with making the frozen balls a hot item on the Internet. She saw them while walking with her dog and her heart melted.
"I have a small English bulldog and they were as tall as her. They were pretty massive," she said, according to UPI.com.