– What weekend of winter endurance sports combines fat-tire biking, hundreds of ice luminarias and one of the biggest cross-country ski races in North America?

No, it's not the City of Lakes Loppet ski festival or the American Birkebeiner ski race.

It's the Book Across the Bay and the Bike Across the Bay.

The two events, a candlelit cross-country ski race and a bike race across the ice, are held on the same weekend in February on Chequamegon Bay, a frozen inlet of Lake Superior in Ashland and Bayfield counties in northern Wisconsin. It's easy to do both for a unique winter duathlon experience.

The Book Across the Bay is the older event, getting started in 1997 when organizers sponsored a nighttime 10-kilometer race across the bay as an offbeat event to break up the long winter and to raise money for the Washburn (Wis.) Public Library.

They hoped for 100 skiers that first year, but more than 350 showed up to race past ice luminarias made in 5-gallon pickle buckets, according to an event history.

When the race was held for the 22nd time Feb. 17, more than 3,000 skiers, snowshoers and runners from 39 states toed the line, said Ben Thoen, one of the race directors.

As the sun was setting, waves of skiers gathered on the shore of the lake in Ashland.

When it got dark, they raced on packed, groomed snow on the lake, guided by about 1,000 ice luminarias lining the groomed course.

Despite the candles, it gets pretty dark in the middle of the lake. But there were bonfires at rest stops and a snow-sculpted dragon that belched real flames marking the 9-kilometer mark.

At the finish on the Washburn shore there was a heated tent with hot food, a band and fireworks. For a registration fee of only $20, it was a bargain as these things go.

Over two decades, Thoen said, the race has only had one price increase. He said it accepts entrants as young as 4 and as old as 89.

"We want everybody to be able to come out," he said.

The event has grown into the second largest cross-country ski race in North America, he added, second only to the American Birkebeiner in Hayward, Wis., about an hour to the southwest.

If you bring your fatbike along with your skis, you can also race in a sister event, the Bike Across the Bay held on the Washburn shore on the morning after the Book Across the Bay.

Started three years ago by the North Coast Cycling Association, the bike race on the frozen lake has 10K and 20K options and race categories for studded and unstudded tires.

Race conditions on the Big Lake can vary from bare ice to crusty snow.

"When you're on Lake Superior, it's like an adventure to be out there," said Joe Groshek, president of the cycling group. "It's more than just a competitive experience."

This year, 62 racers showed up to pedal on mostly packed snow, starting with a LeMans-style start in which the all the racers lined up on foot and had to run about 100 yards to a line of parked bikes before they could hop on and start pedaling.

As with the Book Across the Bay, racing on ice means there are no hills to climb, barring a pressure ridge or two. But the wind seems to blow unimpeded across the bay, so smart racers, both skiers and bikers, draft behind their competitors.

The Bike Across the Bay is also a bargain: Only $15.

Mark Abeles-Allison, a 55-year-old Washburn resident, participated in the race with two 17-year-old foreign exchange high school students staying at his home, one from South Africa and one from Pakistan.

"A definite must-do event for those looking for something out of the norm, riding a bike on Lake Superior ice in February," Abeles-Allison said.

Groshek said he is hoping the race will grow. This year his organization sent fliers about the event to bike shops in the Twin Cities. He said he'd like to eventually see about 200 bikers or more at the event.

"Our goal is simple: To get people to enjoy biking and to enjoy the lake," he said.