Excerpt: From 'Alone at the Top,' by Lonnie Dupre with Pam Louwagie

Editor's note: In January 2015, Lonnie Dupre of Grand Marais, Minn., reached the summit of Mount Denali, the tallest mountain in North America. He did it alone, and he did it during the coldest and darkest time of year.

In his new book, written with Star Tribune reporter Pam Louwagie, he tells how he almost died in the attempt.

Before falling asleep, I put in a set of earplugs to dampen the sound of the rattling tent walls and made myself think of something positive. I was snug and warm there, and I was safe. After retrieving my supplies in the morning, I could rest for a couple of days. I didn't even bother setting my alarm, knowing I could get up at my leisure. All I had to do the next day was ski down to grab my stuff, then haul it up. It would take only a couple of hours.

Oh, man, does this feel good, I thought as I drifted off, unaware of the wind continuing to increase outside.

The tent walls rattled violently when I woke the next morning after nine. I zipped open the door to a sea of white. I couldn't even see the giant rock slope about one hundred yards to the north.

I got dressed and got out of the tent to assess the situation. A foot of snow covered the supplies that I had left outside. I was in a protected amphitheater so I wasn't feeling direct winds, but strong gusts had managed to whip up the snow. It swirled around me as in one of those snow globes people display at Christmas. Thin lines of flakes obscured not only the dark rock wall but also the icefall and the saddle leading up to Windy Corner. Really, all I could see was my tent next to me, which had been buried even more by the snow. I knew I wouldn't be getting my cache that day.

Traveling in whiteout conditions is like pulling a sheet over your head and trying to find something without falling into a crevasse or falling off the edge of a cliff. You can't see dropoffs or rocks until you're right on top of them. The only reference to direction is the way the wind pushes you.

I had sat through many whiteouts before, and I didn't expect this one would last long. I dug out the one day's ration of food I had left in the sled — a gallon-sized Ziploc plastic bag stuffed with snacks that would serve as a breakfast, a lunch, and a dinner — and set it to the side of my tent. It wasn't much, but I still had the emergency supply in my backpack. I started to organize my belongings, and when I finally got around to unzipping the backpack, my stomach sank.

What?

I dug deep into it.

No food. No fuel. Just some extra clothes, an emergency locating transmitter, and my phone.

How was that possible? I kept rooting around in the pack. Had I missed it somehow? It couldn't just disappear. I always carried three to five days' worth of food and fuel with me.

Then I remembered. A couple of evenings earlier, I had rearranged some of my supplies. I often redistributed weight between my sled and backpack depending on the depth of the snow and the incline of the mountain. In steep spots, I wanted more weight on my back for traction, but on flatter terrain, I wanted more weight in the sled. Then I would normally take stock of everything at camp, making sure I knew what to double-carry and what to keep with me at various points. It wasn't always a perfect science. But had I really forgotten to re-stash the emergency rations in my backpack?

I went back outside to the sled and went through everything. I found nothing there, either. Back in the tent, I spread out all my food to take stock. After everything I'd eaten the night before, I had about one day's worth of food left: a couple of chocolate bars, two energy bars, some bacon, a rice pudding breakfast, a partially eaten dinner, a pack and a half of Clif Blok energy chews that I had planned to use for the summit climb, some homemade sesame seed butter, and honey bars. I shook my fuel canister and guessed I had about two and a half days' worth of fuel left.

Calm down, I told myself. Don't get your underwear in a knot. There was a pretty good chance the winds were going to quiet soon, and I would be able to go get the rest of my supplies. If not that day, surely the next day. All I needed was a short window of decent weather. If I could just hike a little way around the corner, I knew I would be able to see my spruce pole. It wasn't that far.

I settled in for a storm day, passing the time by sleeping, completing small tasks, and trying not to worry. Between naps, I duct-taped tiny holes that had appeared on some of my jackets. I taped together a couple of bamboo wands to make larger markers for the cache I planned to leave at that camp so I could find it on my descent. I refined my game plan for what I would carry as I moved higher up the mountain. I switched out two layers of socks on my feet. While my boots were off, I used a spoon to scrape the ice that had accumulated inside them from my foot moisture. I pulled out the waffle-weave rubber insoles and popped out the tiny ice chunks that had formed in them, like ice cubes in a tray.

The tent shook violently in the wind. I worried that it might get damaged, but I thought I had it shored up well enough. Every now and then, I would stick my head out the tent door to see what was happening outside. The air temperature felt balmy; I estimated twenty degrees. But the visibility was still horrible.

I ate only a couple of bites at each meal the rest of the day, trying to conserve.

All the while, Denali seemed to tease me. For short periods, I could see the rock slope, but ten minutes later, blowing snow would sock me in again.

I turned on the radio, and at one point a news segment mentioned a Minnesota man and his quest to successfully climb Denali solo in the dead of winter. "I know that poor sap!" I said aloud.

I talked briefly with Stevie over the satellite phone at about 7 p.m., trying to get a fix on the weather and my situation. As the evening wore on and the winds grew stronger, I was reluctant to open the tent door, trying to keep snow from flying in and melting. But I had to go outside at times to scrape the snow from the tent walls and keep the storm from consuming me. All bundled up, I tried to dart out as quickly as possible, rushing to zip the door shut behind me.

Later that evening, the wind whistled and snapped my tent fabric so much that I decided I needed to better protect my little haven. I got up, pulled on ice-cold clothes over my long underwear, and went outside to sink the tent further into the snow.

I had secured the tent by attaching it to equipment or stuff sacks filled with snow, then burying them, a technique called a deadman anchor. I unfastened a few of the anchors at a time, digging under the tent, then refastening as I went. The cold wind drove snow into my face, my cuffs, and the creases of my neck. Sinking the tent created walls of snow around it. I wondered how long I would need those walls.

Reprinted with permission from "Alone at the Top: Climbing Denali in the Dead of Winter," by Lonnie Dupre with Pam Louwagie, published by Minnesota Historical Society Press.