Colin O’Brady is fighting to be heard over howling winds in Pakistan’s Karakoram Range. It’s lunchtime and the American adventurer has just descended from camp one on K2, the world’s second highest mountain, after spending two nights waiting out a storm on a precipitous ledge.

Even at base camp, which sits at 5,100m — higher than the summit of Mont Blanc — overnight temperatures have dropped close to minus 40C, reaching a high of minus 15C by day.

“Every morning you wake up there’s frost inside the tent from condensation covering your sleeping bag and the tent walls,” O’Brady shouts on a satellite phone call. “This mountain really lives up to the hype and I haven’t even got that high yet.”

O’Brady is part of a small army of more than 70 climbers, guides and sherpas attempting to make history on K2. A forbidding pyramid of rock and ice, the 8,611m mountain is only 238m shorter than Everest but it dwarfs its Nepalese cousin as a challenge thanks to its steeper slopes and the potential for hurricane-force winds.

At the notorious Bottleneck couloir, a few hundred metres from the summit, car-sized blocks of ice can break off from the glacier above without warning — survival is a game of chance.

The world has 14 peaks that pierce the “death zone” above 8,000m — where oxygen levels are so low that the body begins to deteriorate and thoughts become muddled — but only K2 has never been climbed in winter, when the snow is deeper, the avalanches are bigger and the cold is much, much colder. O’Brady, 35, and his rivals now shivering on the mountain, are hoping to bag one of the last great prizes in high-altitude mountaineering.

In a dizzying 14 years between 1950 and 1964, all 14 of the highest peaks were climbed in spring or summer, including Everest in 1953 and K2 the following year. In the 1980s, a small group of especially masochistic mountaineers began the far slower task of conquering the peaks in winter; when Broad Peak was finally climbed in the winter of early 2013, then Nanga Parbat in 2016, it left only one summit outstanding.

A winter ascent of K2 would complete a 70-year mission to test human limits on the roof of the world. But the size and nature of this year’s assault, which vastly outnumbers previous winter attempts — and includes amateurs on commercial trips who come armed with Instagram accounts and gallons of oxygen — is filling even hardened mountaineers with fear.

“It’s called ‘Savage Mountain’ for a reason and it wouldn’t take much to turn it into hell,” says Kenton Cool, the British mountaineer and guide who has reached the summit of Everest 14 times. “On any 8,000-metre peak you’re battling to stay alive. Now add the fact that it’s K2 and it’s in winter . . . I’m gasping for air just thinking about it. We could easily see multiple deaths.”

Cool, 47, is concerned that some members of the commercial parties on K2 aren’t up to it. “I question the moral standing of a company that would take someone with almost zero experience [of 8,000m peaks] to K2 at all, let alone in winter,” he says. “Step outside even at camp two and, if your systems aren’t dialled, you’ll lose fingers in minutes. K2 won’t tolerate mistakes.”

Even in summer, K2 is among the deadliest mountains. To date, according to the best available statistics, there have been 478 ascents of the mountain and 87 deaths — one death for every 5.5 successful summit pushes. On Everest, where there have now been more than 10,000 summit climbs, the ratio is around one death per 33 ascents.

Chart showing fatality rates on the world

In 1995, Alan Hinkes was one of five people to reach the summit of K2. Days later, seven climbers died in a storm, including his good friend and fellow Brit Alison Hargreaves. The mountaineer, who had shot to fame by climbing Everest alone and without bottled oxygen, is thought to have been blown off the summit ridge. Her son Tom Ballard went on to become a climber but was killed in 2019, attempting to climb a new route on Nanga Parbat in winter. He had also planned to take on K2 to honour his mother.

Hinkes, 66, tells me he is “flummoxed” by what is unfolding on K2. Even in summer, he says, “Nothing would make me go back to K2. If someone offered me a million quid, I just wouldn’t go back. I wouldn’t be prepared to take that risk again.”

The handful of previous attempts on K2 at this time of year, dating back as far as 1988, have involved small groups of experienced 8,000m winter climbers. But in the modern business of adventure, genuine firsts are in dwindling supply. When commercial operators marketed K2 in winter and Pakistan opened the mountain after a cancelled summer season, O’Brady joined the party.

The American former triathlete climbed Everest in 2016 but found fame in 2018 after claiming another great first — a solo and unassisted crossing of Antarctica. He was heralded by the press and on TV chat shows but the expedition became controversial after he was accused of playing down the fact that, for some of the way, he was following the compacted trail used by vehicle convoys en route to the US South Pole base (he denies misleading anyone).

Map showing himalayas K2: the normal route up the Abruzzi ridge to the summit

O’Brady is supremely fit and used to extreme cold. But by signing up with Seven Summit Treks, a Nepalese company providing guides, infrastructure, fixed ropes, sherpas and oxygen to the majority of the climbers now on K2, he has walked into another storm of debate.

Alan Arnette, an American mountaineer and respected climbing chronicler, who climbed K2 in 2014, says the company has cornered the market in relatively affordable guided mountaineering (reportedly up to $45,000 for the current expedition). “It’s almost like a Ryanair business model, where the costs are low and not many questions are asked,” he says. “You’ve got people who lack winter experience alongside world-class athletes who know exactly what they’re doing.”

O’Brady, who has more than 250,000 Instagram followers and is sponsored by an energy bar company, says he is only using the company’s permit and some infrastructure, but is otherwise climbing with his friend Jon Kedrowski, who also has experience at 8,000m. Less visible in O’Brady’s Instagram photos and uplifting captions are the two sherpas helping the Americans.

O’Brady, who acknowledges the sherpas on the phone, insists the scale of the expedition provides safety in numbers. “I think the way things are structured right now gives us the highest chance of success,” he adds.

Chhang Dawa Sherpa, the expedition manager at Seven Summit Treks, who has climbed all 14 8,000m peaks, bats away criticism of his company and questions about the experience of some of his clients.

“There are always perceptions and opinions in mountaineering,” he says by email. “I believe we have good management, a good and strong Sherpa team, and experience. However, there are always certain and uncertain risks, especially in K2 in the winter. I just can say we will try our best. If the mountain, health, weather and teamwork favour us, we will take the summit.”

Map of Pakistan

Dawa’s brother Mingma Gyabu Sherpa is leading the Seven Summit Treks team. After decades of assisting western climbers, often without credit, Dawa also says it would be an “historic achievement” for a Nepalese mountaineer to make the first winter ascent.

Mingma G, as he is known, has competition from Nirmal “Nims” Purja, a Nepalese former Gurkha and British special forces soldier. Nims, who lives in Hampshire, became a breakout star of mountaineering in 2019 when he climbed all 14 8,000m peaks in a record six months and six days (the fastest the feat had previously been achieved was just under eight years). Sponsored by Red Bull and Osprey, he is leading a smaller group with his guiding company, Elite Himalayan Adventures, albeit with eyes on his own summit bid.

Yet Nims, whose strength and talent have won numerous plaudits, has also become a lightning rod for criticism from some quarters thanks to his reliance on supplemental oxygen and facility with social media. For purists, using oxygen to climb is like running a marathon on roller skates.

“You can always go again without oxygen if that is what is so important, but you can’t if you’re dead,” Nims said in 2019. O’Brady says he hasn’t decided yet whether he will use it on K2, and that he will declare it if he does.

For some observers the potential for disaster on K2 this winter carries echoes of Everest in 1996, when a vicious storm killed eight climbers close to the summit. Four others perished during what was then the deadliest season on the mountain. “No one wants such tragedy this time, but the elements leading up to this K2 season do produce a sense of déjà vu,” suggested an article on the specialist website

The Everest disaster, which inspired Jon Krakauer’s book Into Thin Air, triggered a bout of soul searching about the commercial expeditions that were beginning to crowd the mountain. Experience and skill seemed to matter less than cold cash and bragging rights.

Nevertheless, commercial climbing went on to become well established on K2 in summer. Mass disaster struck the peak again in 2008, when 11 people died at the Bottleneck. “People today are booking these K2 package deals almost as if they were buying some all-inclusive trip to Bangkok,” Reinhold Messner, the Italian legend who was the first person to climb all the 8,000m mountains, said after the deaths.

Ralf Dujmovits partly blames himself. The German climber and guide says he was the first to take clients to K2, in 1994. “And we were a really strong team,” he tells me. “Now the professionals are still organising small expeditions, but those who join commercial expeditions totally depend on guides and oxygen.”

After the 1996 Everest disaster, Dujmovits stopped accepting clients who needed extra oxygen. For him, its use was a threat to life as much as style; when equipment fails or supplies run out, climbers who could not otherwise reach the death zone become fatally exposed.

“There are no resources to save people at 8,000m in winter on K2,” says Adrian Ballinger, an American mountaineer and guide, who climbed K2 in 2019. “If you can’t get up and down by yourself, you will not survive.”

Dujmovits, 59, assumes most climbers won’t make it far above 7,000m. But he is most concerned about K2’s lower slopes, where camps are small and exposed and rocks dislodged by other climbers become deadly missiles.

He also fears that the pressures of public profiles might skew attitudes to risk. Like O’Brady, Nims is aware of the need to update his followers. Late one day earlier this month, after fixing ropes up to about 7,100m, he took off his glove to take a picture for his 250,000 Instagram followers. “This selfie might have cost me a small dent in my fingers or two,” he wrote, adding a winky-face emoji.

“There are some climbers who are very, very ambitious and I hope they aren’t committing suicide up there,” Dujmovits says. O’Brady says he has no death wish. “Nothing is more important than making it home safe and sound, back into Jenna’s warm embrace,” he wrote of his wife Jenna Besaw, who had made the two-week trek with him to base camp.

After last week’s storm forced a mass retreat to base camp, climbers took part in a Puja ceremony, in which a Buddhist lama blesses them and their equipment. It may not be enough, but if the weather clears in the coming weeks, O’Brady says reaching the summit would be his greatest achievement. “But my hope is that myself and all the other climbers up here are safe. That’s the important thing. Pushing limits is something I love, but —”

Somewhere even higher above Pakistan, a satellite moves out of reach, and the line goes dead.

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