Visitors to the highly anticipated opening of the Apostle Islands ice caves in northern Wisconsin on Saturday morning will have to contend with an extremely treacherous walk of at least a mile on Lake Superior. But national park officials say the reward will be worth it: views of the lake bottom in spots, ice plates piled like broken glass, long icicles draped and dangling on sandstone cliffs.

Last winter, a record 138,000 visitors trekked to the caves over the couple of months that they were accessible. It was the first time the caves were open in five years, and word of their beauty went viral on social media.

The visitor deluge cost the National Park Service far more than it took in from charging $3 per car for parking in its small lot. Staffers worked to answer phones and e-mails, direct traffic, plow snow and clean restrooms as well as rescue visitors who hurt themselves on the ice. Now the park will be charging a $5 fee for each ice cave visitor 16 and older. The money will be used solely to cover the costs, park officials said.

Because ice conditions can change quickly, officials warned that the caves could have a short window during which they are accessible. To check conditions before making the trip, call the Ice Line at 715-779-3397.

If you’re one of the hardy ones who make it this weekend, share your photos with us via Twitter and Instagram with the hashtag of #stcaves.

PAM LOUWAGIE