There are high hopes the mainline ice caves at the Apostle Islands National Lakeshore will open this winter after three years of no access.

Park officials say the next few weeks are crucial to determine if visitors will be able to witness the dazzling ice formations this season or whether they’ll have to wait another year.

The caves are a hit-or-miss phenomenon. For the ice caves to open, there needs to be a sufficiently thick layer of ice on Lake Superior for people to make the miles-long trek to the formations.

“You need the right conditions so that people can get out there,” said Julie Van Stappen, chief of planning and resource management for the Apostle Islands National Lakeshore. “The best conditions for ice formation is when it’s really cold and really calm.”

After a warm December, the region’s recent cold freeze helped form more ice along the south shore of Lake Superior in northwest Wisconsin. But strong winds last week broke up ice and stymied progress.

A photo posted on the Apostle Islands’ Facebook page Saturday shows ice on the lake is patchy, with round sheets of “pancake ice” floating on the surface.

The sea caves are carved along Lake Superior’s coast on the northern tip of Bayfield Peninsula. During winter, waves splashing against the sandstone cliffs — along with water seeping down from rock layers — freeze on the rock formations, creating a magnificent array of icicles, crystals and sheets of ice.

The cave’s unique ice structures form every winter, regardless if there’s access to the caves or not. But jagged “shark ice” sticking up along the coast has prevented even trained park rangers from going out on Lake Superior this winter to see what they look like.

When accessible, the caves have become wildly popular. In 2014, more than a hundred thousand people flocked to the area to witness the caves firsthand. A much shorter season in 2015, just nine days, still drew thousands of visitors.

“It was really more a local phenomena until 2014. And then all of a sudden the whole world discovered it, which was really cool,” Van Stappen said.

But warm weather has prevented public access for the last three winters.

Although there’s ice forming on Lake Superior this year, Van Stappen said, the sheet of ice needs to be locked in place between several islands and the mainland to ensure safety.

“It went from no ice to pack ice, which formed really quickly,” she said. “It’s jumbled up ice and it’s not high-quality at this point.”

Park ranger are monitoring conditions over the next few weeks to gauge if ice becomes safe enough to walk on. The park posts regular updates on its Facebook page and the park’s website.

But the “million-dollar question” remains: Will we get to see the ice caves this year?

“It’s hard to say,” Van Stappen said. “It’s all dependent on weather conditions.”


Austen Macalus is a University of Minnesota student on assignment for the Star Tribune.