JACKSON, N.H. — You have to think of it like burning matches, the skier told me. That was the best way he’d heard to describe it. You don’t want to burn too many because you can’t unburn them, but you don’t want to leave with any you haven’t lit.

When he told me this, it was at the start of lap nine, back when the race was still festive, back when the skiers only said lucid things, long before the levitating Amish women seen on night three.

The skier talking about matches was a 24-year-old named Aidan Crawford, who was just about to start back up the mountain with the 74 competitors who remained, out of the 100 who had answered the 10 a.m. gun for this painfully simple race. All you have to do is ski a mile and a quarter up to the top of Black Mountain, to the spot where the beloved vintage double chair lift unloads, and then ski back down. You have an hour to do it, and if you do, you do it again, every hour on the hour, until you can’t. One person will be “The Last Skier Standing.’’ Everyone else is marked “did not finish.’’

As Crawford disappeared into the darkness on lap nine, the first after sunset, I shouted to him that I’d see him in the morning. “Maybe not,’’ he shouted back, which turned out to be true.

At 5:42 a.m., he was not one of the two dozen skiers who skidded down the final hill in a pack of headlamps and began the busy turnaround prep that would make the next 18 minutes fly by. Most clicked out of their skis and immediately spent the couple minutes it would take to convert them back into uphill skis, adjusting the bindings and adding fabric skins to the bottom to grip the mush and ice left behind by a 51-degree February day that was but a memory now.

Temperatures had returned to the teens during a night that took out 50 people, and now all anyone could talk about was the sun, which promised to arrive during the next lap. In two large support tents, some forced down coffee and pancakes, while others took a stab at a second of sleep, reclining in chairs with sleeping bags over their eyes. Everyone one else was working on a blister or running a massage gun over their thighs.

All too quickly, they were called to the start line, and as they waited for the click of the hour, one of the skiers got a halfhearted laugh with “I feel like we just did this.’’ Then they set out on lap 21.

Running the race were the founders, Andrew Drummond and Monte McIndoe. A few years ago they’d hosted something similar on property Drummond’s family owned, a running race called Bubba’s Backyard Ultra, before bringing it to the snow and Black Mountain two years ago. The first year’s event had lasted 34 hours, which feels almost quaint now. Last year’s went 61.

“Where’s the sun? Where’s the sun at?’’ Spencer Ralston shouted at me as I walked alongside the pack for the sunrise lap. In boots, I had no problem keeping up on the lower half of the mountain, which wasn’t terribly steep, and Ralston, who is a big character, even at that hour, was happy for the audience. He informed me that he had some minor chafing and the monotony was seeping in, but it was going much better than last year, when he’d had to quit after 14 hours when his stomach turned on him.

“This is Type 2 fun,’’ he explained. “Type 1 fun happens in the moment, but Type 2 fun arrives much later, when you can look back like, ‘Damn, I can’t believe I did that.’’’

Ralston looked at his watch. “We’re 20:15 in, and 21,500 feet of gain. You’ve got to laugh at us. We paid money to do this, to give our lives meaning when we sit at our desks.’’

About three-quarters of the way to the summit, the course enters a narrow, icy trail through the woods, then comes to a section so steep that most everyone clicked out of their skis and bootpacked to the summit, climbing frozen steps left by the footprints from the laps before. Ralston stopped talking to concentrate, and after rounding a bend, he was greeted by a stunning dawn view of Mount Washington, completely and uncharacteristically clear.

The skiers in his group paused for a moment, each of them, to take in the view. But only for a moment, because they had to take their skins off, adjust the bindings again, then ski down as quickly as they could to savor whatever minutes remained until the hour clanged.

By the afternoon, 28 hours in, only a dozen skiers remained for the lap when they would “Everest,’’ reaching a cumulative 29,032 feet of vertical gain. This was also the lap when they would start to miss the pre-game stuff for the Super Bowl, so I excused myself and watched the game from a hotel room as they skied into night two. When I returned before dawn, their numbers were down to three.

Most skiers were pacing between 42 and 50 minutes per lap, but at 6 a.m. Monday, I walked lap 44 with a 34-year-old from Ohio named Brody Leven who identified himself as a “professional human-powered skier’’ and had been hitting 39 minutes a lap like clockwork, always at the front of the pack.

“I seek out testing myself. I live for this,’’ he said, reading off the vertical gain from his watch, now showing 46,771 feet. “I’m competing against them, but I’m competing against myself. And I have no intention of stopping.’’

He thanked me for walking with him. The previous lap had been one of the toughest, he said; more than once his eyes had rolled straight into the back of his head and he just kept walking, except for when he stopped to check on a guy who was bent over working on his car, only to discover it was a tree and a rock.

At the summit he turned and raced down, and I talked with Andrew Drummond, one of the founders, who said what was magical about Last Skier Standing is that it takes two people to push each other, but one is destined to end up being “the assist,’’ the noble and painful role of taking it as far as they can but not far enough.

Before I could get down the mountain, the three skiers were again coming back up. Leven was in the lead with his headphones in, and he climbed past me like a ghost, like he didn’t even know I was there.

Just behind him was Ben Eck, a 29-year-old from Somerville, and when I tagged along with him for lap 45, he was moving far more deliberately, as he had from the start, a noteworthy tactic because Eck was the defending champion, the 61-hour legend.

Last year, on a whim with no real training, Eck had started the race on Saturday morning and not stopped until late Monday night, a feat that brought him immediate status in the small world of ultra-endurance sports. It had also left him feeling a bit scarred, he confessed, and as I walked with him on Monday morning, he made clear that he would be perfectly happy if he didn’t have to break his record this year.

“If I think of this as competing with myself, then I need to go more than 61 hours, and I really don’t want to have to do that again,’’ he said. “But that’s what’s amazing about this race. In any other race, you know when the pain will end. Here, who knows? It goes on as long as you want if you’re stubborn, and I’m pretty stubborn.’’

The 48-hour mark came and went, and it remained down to Leven, who didn’t take any caffeine; Eck, who is a grad student in environmental engineering at Northeastern University; and Rich Connell, a 38-year-old from Middlebury, Vt., who introduced himself to me as one of the three “survivalists.’’

“Is that the right word? My brain is not working,’’ he said as he tapped the air as if with a wand, using his ski pole to conjure up the right word. “Survivors. That’s it. Survivors.’’

Leven saw the levitating Amish women somewhere in here, and by lap 57 — after they had double-Everested — Connell dropped and it was down to Eck and Leven, the tortoise and the hare, who together pushed through last year’s record and into a fourth day.

“I’m pretty excited we made it to Tuesday,’’ Eck said. “That’s good. That’s funny.’’

But after lap 64, as they sat in the big tent and 2 a.m. approached, Eck spoke aloud of being worried about the downhills. He still had uphill left in him, he said, but skidding down the icy mountain in the dark felt like a wreck waiting to happen.

“I just like them the way that they work now,’’ Eck said looking at his knees. “They’re good the way they are.’’

He hadn’t officially said it yet, was still searching for the answer, but you could feel it coming and he turned to look at Leven for a clue.

“It seems like you could kind of go uphill all night,’’ he said to Leven, who shrugged.

“Yeah, I just won’t stop,’’ he replied. “I don’t know what to say.’’

“No, no, that’s good info,’’ Eck thanked him. “Yeah, I’ll call it, man. I don’t need to do that any more.’’

Per the rules, Leven went out and did lap 65 by himself, winning himself the title, the $1,000 prize, and — after 169.2 miles, 69,539-feet of vertical gain, and discovering he that he can in fact sleep walk, or at least sleep ski -- permission to stop.

But it would take a few days, Leven said, for him to figure out what was most interesting about the race, an epiphany that came after a shower, a few hours of sleep at a hotel, a ride to Boston, a flight to Salt Lake City in the back row center seat, and then a full day in a suit at meetings lobbying for Protect Our Winters (he’d raised pledges each lap for the nonprofit; Eck had done the same for the Native Land Conservancy).

“Everyone gets to find their limit except the winner,’’ he said over the phone, with an unmistakable hint of sadness. “It would be a complete coincidence for the second-place person to quit one lap before the winner would. They pushed themselves to where they had to quit, which is so admirable, so cool. They found their limit. But I never got to find mine.’’

Next year was a long way away, he said. But it was the only way to find out.

Jessica Rinaldi of the Globe staff contributed to this report.

Billy Baker can be reached at billy.baker@globe.com.