Lonnie Dupre huddled in his sleeping bag in the frigid darkness, trying to hibernate through his fears.

It was supposed to have been an overnight stay, at 11,200 feet altitude on the west face of Alaska’s Mount McKinley. But for four days straight, unrelenting winds had whipped up a fierce blizzard outside his tiny tent.

Just a measly couple of bites of homemade energy bar remained, along with only 3 ounces of fuel to melt snow into water. He’d been stretching a 1½-day food supply for more than four days. It was still early in his climb on the 20,320-foot mountain, but the snowy white-out meant the rest of his goods — a quick 10-minute ski down the mountain — were out of reach.

“It almost broke me,” he said. “I knew if I was stuck there another two days, I might not survive.”

It was the low point in what would be a 29-day odyssey for Dupre, on his fourth attempt to do what no one had accomplished before: solo summit McKinley in the darkness and cold of January. For three years in a row before that, poor weather had blown away his chances to make the record books. Now weather was again playing havoc with his quest.

Summiting alone is no small feat in any season, but in January there are no other climbers on the mountain, also known as Denali. Temperatures often dip to -50F to -60F at that time of year, Dupre said, and daylight shows for only about five to seven hours at a time.

Dupre tried not to worry about any of that. He had trekked through bitter cold and desolate darkness on many frozen expeditions in his 53 years. He skied to the North Pole twice, kayaked and drove a dog sled around Greenland and crossed the Bering Strait.

But fellow travelers had provided a kind of comfort on all of his polar expeditions. This time, his main contacts were phone calls to his expedition manager and a training partner who provided weather updates.

As the bone-chilling wet snow fell on his tent, he occupied his mind with small tasks: clearing snow from the top of the tent, recording journal entries on his iPod, brushing frost from the tent’s nylon interior, and at one point listening to “A Prairie Home Companion” on a small radio.

He tried not to think of his friends in Grand Marais toasting the New Year. Dupre figured he could survive for about another 48 hours. Rescue aircraft couldn’t land or even drop supplies during a storm like that. He had never felt more alone.

As he lay wrapped inside that bag, fear crept in. He couldn’t let himself freak out. It would be the end of him.

The climb

Dupre had never liked summer. As a boy in central Minnesota, he felt like he would melt while he picked sweet corn in high humidity. When the lakes and creeks froze, he saw them as new playgrounds to explore.

He studied how people lived in harsh climates. He started expeditions to far reaches of the planet in his 20s, bringing attention to climate change with some of them.

But soloing Denali in the dead of winter was more of a personal challenge.

When a ski plane placed him at 7,200 foot-altitude base camp on Dec. 18, Dupre could see the summit he was aiming for. But he wasn’t trying conquer the mountain. He had to respect it, he knew. He had to be patient. Success would come only if conditions allowed it.

Lugging more than 190 pounds of gear by sled and backpack, Dupre doubled back to ferry portions of his supplies up the mountain. He would haul some up, camp there for a night, go back down to get the rest the next day. He carried or wore skis he made from a birch tree on his property in Grand Marais. He carried trekking poles and a long spruce pole to keep from falling through crevasses that might surprise him under the snow.

With each hour, each day, his senses heightened to understand his surroundings.

“You kind of start out domesticated and you turn wild,” he said. “You shed civilization, and you slowly become an animal. And you need to do that in order to survive.”

He relied on those senses to make potentially life-altering decisions. Was the weather good enough to continue climbing that day? Which way should he go? How much food and fuel should he carry to set up his next camp?

Dupre watched the winds and clouds changing around him; he treaded carefully across the crusty snow, poking the ground ahead of him to test for crevasses and other hazards that could be deadly. He monitored subtle changes in his body, stopping immediately to warm chilled fingers or catch signs of dehydration.

He carried enough battery power for two satellite phone calls each day, most often to his expedition manager. He also used a spot beacon to send simple text messages, letting people know where he was and that he was OK.

He spent days and nights chasing away negative thoughts. When he missed his friends, he found or created some small task so he could focus on something else.

As with all his expeditions, he was pushing his own limits and learning about himself.

“It’s the journey of finding out who you are,” he said. “You’ve got a really raw look at your inner self.”

Dupre missed a companion most during the spectacular moments that can’t be fully understood through words or photographs. One evening on Denali, a beam of light shot through a glacier, glaring like a spotlight on a theater stage. Dupre didn’t know what to make of the phenomenon at first. As he stared and the light moved over time, he grew to understand it was moonlight shining at just the right angle, refracted by the glacial ice.

Shooting for the summit

Huddled for more than four days during the storm, Dupre sometimes lay in his sleeping bag, trying to gauge whether the wind was letting up based on the cadence of the flapping ripstop nylon of his tent.

On New Year’s morning, the wind had slowed when he forced his weakened body to rise. The air was far from clear, but he could see just enough, he told himself, to try to get the rest of his supplies.

He strapped on his birch skis and headed back down the mountain. Then more blowing snow moved in, and Dupre found himself traversing crevasses. He realized he was on the wrong path.

Correcting his direction, he searched for about two hours before, finally, he spotted the cache of supplies he had left behind.

He bowed his head and let out a giant sigh before he tore open his food bag and gulped down two chocolate bars. Relief. He would live. His journey could continue.

In the following days, he plodded toward the summit — two treks up, one trek back.

On the morning of the big day, with 3,000 feet left to climb, Dupre set out in the dark for a nine-hour climb to the top. With a headlamp, he climbed a steep, dangerous section that some call the Autobahn: “If you slip you get going really fast,” Dupre said. Then he scampered along a ridge to the top.

Dupre wouldn’t let himself get his hopes up until he was a few hundred yards away and once again had the highest point in North America in his sights. At the top, he broke down in tears.

It had taken him four attempts to get there. Four years of pulling sleds, of trudging up and down, of beating himself at his own mental game. He stayed for 10 minutes — nine minutes longer than he probably should have, he joked — to soak it all in.

As he stood there, alone at the top of the continent, the problems of the world seemed small.

“I was just humbled to be there,” he said, “and be alive.”