The frigid winter has transformed the caves along the south shore of Lake Superior into a glittering icy playground.
Word of the ease with which visitors can take in the natural splendor of the Apostle Island Sea Caves is spreading fast — so fast that more than 20,000 people trekked there over the weekend.
That's great news for area businesses, but it has placed a lot of stress on Apostle Islands National Lakeshore officials, who must cope with the influx of tourists. They've been busy even on a "slow day" like Monday, when the ice caves drew 1,800 people throughout the day.
Decked out in brightly colored down and water-resistant clothing, a long line of hikers stretched along the ice-covered shore.
"It was definitely worth the trek," said Michelle Carlson, who drove over from Hermantown, Minn., to see the caverns coated with icy stalactites.
"When you first walked out here and looked at all the people and how far you had to go, you kind of thought, 'Am I crazy?!'" Carlson said. "But when I got there I was very glad I did it."
This is the first time since 2009 the ice has been thick enough for hikers to safely reach the caves. But five years ago the caves attracted perhaps 1,500 people on a busy weekend day, Chief Ranger Chris Smith said.
This past Saturday, the busiest day yet this winter, there were 11,000.
"It's been overwhelming," Smith said. "We did not anticipate this level of turnout for this."
On weekends cars are parked three to four miles down the road leading to the trailhead. To ease the congestion, Bayfield County is running shuttles to transport visitors to the site.
Five other national parks have sent staff to help, along with local Sheriff's offices, the U.S. Coast Guard and Border Patrol. They've set up an Incident Command Center in a small heated trailer at the trailhead, where on busy days they respond to a dozen or more emergency calls on snowmobile, Smith said.
"We can bring people in here into our little trailer, get them warmed up, keep them in here until the ambulance gets here," he said.
The most common problems are head injuries from slipping on the ice and hypothermia. Several children have been separated from their parents.
Smith said while most people are prepared for the elements, park personnel do see visitors who couldn't be more unprepared.
"We do have some horror stories of people wearing high heels and shorts," he said. "We've had a lot of older people come out with canes and walkers and all that. They try to get out there, they get injured [and] we have to go out and wrap an ankle or something like that and bring them in."
Anyone wondering what has lured so many people to the frozen, remote corner of Wisconsin need only look at the flurry of media coverage — as reflected in the more than 24,000 articles found on a Google News search.
But park officials and others attribute most of it to posts on social media sites, particularly those on Facebook. They've sent a flood of visitors to the ice caves.
"The first Sunday, we just filled up with people, and it totally took us off guard," said Cheryl O'Bryon, who runs the Village Inn bar and restaurant in nearby Cornucopia. "Talking to those people, they had seen people's posts from the Saturday, that day before, when it first opened, and then that just goes viral."
O'Bryon has had guests from as far away as Australia and China. On recent weekends she has served more than 400 people a day, "which is 385 people more than we would have last year at the same time," she said with a laugh.
The Park Service estimates about 50,000 people have visited so far — more than come to the area most summers. The Bayfield County Tourism estimates those tourists have spent as much as $10 million.
No one knows how much longer this unexpected tourism boom will last.
Smith said the ice could remain safe for several more weeks, or just a few more days. His advice for tourists: be safe, enjoy the spectacle, and plan for a lot of company.
"There will come a time when the ice looks safe and it won't be, so getting compliance is going to be crucial," he said. "Because you go in this water, and we're not out here, your odds of survival are very slim."