As temperatures dip and snow piles up in the mountains, even the most avid Colorado cyclists are stowing away their bikes for winter. But not David Clark. The Boulder resident is about to spend the month of January on the saddle of his fat bike, embarking on a 2,000-mile mid-winter ride across the country.

Clark will depart on Sunday, January 5, and plans visit the six original NHL teams’ stadiums—starting in Chicago (Blackhawks) and pedaling to Detroit (Red Wings), Toronto (Maple Leafs), Montreal (Canadiens), Boston (Bruins), and ending with his home team in New York (Rangers).

It might seem like a goal that is equal parts extreme and insane—but there’s a reason for this journey. Fifteen years ago, Clark fought his way back from morbid obesity and addiction by focusing on extreme endurance events, including the Leadville 100, one of Colorado’s most grueling ultra-running races.

“That, for me, seemed so impossible,” Clark says. “It’s so easy to dismiss your accomplishments. Lots of people do marathons and Ironmans. I knew that if I could run 100 miles that wouldn’t be something I would ever dismiss.”

Since then, Clark has run the Boston Marathon four times in one day, spent 48 hours on a treadmill, covered 40 miles a day on foot during a three-week cross-country trip, and ran 343 laps on a track in honor of the 343 firefighters who died in the September 11 attacks.  Many of his athletic achievements have had a charity component, but when his dad was diagnosed with bladder cancer two years ago, Clark decided to do something more personal.

“Hockey has been this glue for the males in my family,” he says. “I wanted to do something that blended the endurance sports that saved my life with hockey, and do something really positive for people battling cancer like my dad. ”

Part of Clark’s ride will be broadcast on NHL network where viewers will be encouraged to donate directly to Hockey Fights Cancer, the NHL’s charity. Clark also hopes to get bikes, helmets, and jerseys signed by players at each of the stadiums to auction off.

Even with a decade of insane challenges under his belt, Clark sees this one as bigger than anything else he’s done. Specifically, because he is doing it in harsh winter conditions where training can only get you so far.

“Doing it in January really is the unknown factor,” he says. It’s going to be mentally tough. I’ve learned to trust myself to figure it out. Understanding that I’m just going to have to work in the moment, one pedal turn at a time if it comes to that.”

Anyone who has been on a bike in even mildly cold temperatures can attest that a light breeze can become a demoralizing head wind and a brisk chill means frozen fingers. In negative 15-degree weather and with a high likelihood of rain, snow, and wind, Clark is going to have to experiment with layers—too many means hot and sweaty, too few equals frostbite.

“Staying warm is the toughest part of it. I’d be lying if I said I had a clear idea until I actually get out there,” he says. “I’m just trying to have as many options as possible so I can tweak as I go.”

But of course there are other things that can go wrong. Snow, water, and salt can cause components of the bike to malfunction. Most are minor, except when you’re in the middle of rural Canada and 80 miles from a bike shop. Clark plans to have a van following him for equipment, logistical, and moral support. A few friends, including actor Tom Arnold and former UFC welterweight champion Pat Miletich, have promised to ride a couple days with him along the route.

But Clark is taking an even bigger risk with this ride than just the physical. When his father was diagnosed with cancer the second time, doctors said he wouldn’t survive the trip home. That was over two months ago. To say it bluntly, there’s a chance Clark’s father could die while he is on a bike in a snow storm in the middle of nowhere.

“I’ve gone back and forth so many times,” Clark says. “I want to do it while he is still around for him to see it. He might not be able to see the start of it or see the end of it, but I want to do it while he is still here. We don’t sit around and wait for bad shit to happen before we do something great. My dad didn’t teach me that. That’s not who we are.”