On April 30, the climbing world lost one of its all-time greats when Ueli Steck fell from approxmately 7,100 meters on Nuptse in Nepal. He was 40 years old. In typical style, Ueli was climbing by himself, with nothing more than a day pack containing minimal supplies.

Ueli Steck grew up in Langnau in the Emmental Valley—rural Swiss cow country, far from the bright lights of Zermatt or Interlaken. He was the youngest of three boys and came from a family of athletes: His two older brothers played competitive hockey, but Ueli discovered climbing at the age of 12 and resolved to follow its pull instead. “I don’t care what you do,” Ueli’s father, Max, told him, “just do it 100 percent.” Ueli quickly excelled, climbing the Eiger’s north face for the first time in 1995, when he was 18 years old.

Around that time, Ueli came under the wing of Kari Kolber, a veteran Himalayan guide who introduced him to the mountains of the Khumbu Valley, bringing him along as an assistant guide on a trip to Ama Dablam. While their clients rested, Ueli snuck out of base camp, summited the mountain, and returned that day—setting one of the first speed records of his career.

Ueli did his mandatory service in the Swiss Army, then trained as a carpenter, but mostly he climbed. In 2001 he ticked new routes on the Eiger and Pumori in Nepal; in 2002, he managed Blood from the Stone, a phenomenal mixed line up the east face of Mt. Dickey in Alaska. From the start of his career, friends noticed his drive. “He had a lot of talents,” wrote Kobler, “but the most important thing is: I don’t know any other mountaineer...this goal-oriented.”

The Eiger kept calling. In 2004, Ueli soloed the north face for the first time. By 2007, he felt ready to attempt the speed record. It took several tries before he succeeded, cutting the previous mark by 46 minutes, to 3 hours 54 minutes. But Ueli wasn’t done. In 2008, he fully invested himself in a training program designed with Simon Trachsel of the Swiss Olympic Training Center. In December of that year, he broke his own Eiger record by more than an hour.

It is somehow fitting that this signature achievement was more a statement of inner mastery than external achievement. It is also one of those perfect little ironies of life that such an intensely personal experience would rocket Ueli to new levels of professional stardom and public scrutiny. After the record-breaking ascent, Ueli and a close friend, photographer Robert Bösch, self-funded a shoot using a helicopter to capture Ueli re-soloing sections of the climb. The resulting footage of him literally racing up the Eiger’s snowfields and insecure limestone appeared in the hit movie The Swiss Machine, stoking the imaginations of millions of people.

I met Ueli at the Banff Mountain Film Festival the following year. In front of a rapt audience, he told the story of his Eiger solo with pitch-perfect modesty and self-deprecating humour. The year after that, we climbed together in Nepal and I discovered how much the public persona I had seen on stage at Banff was simply a professional role for him to fullfil, rather than a personal calling. Ueli was a natural introvert who preferred exercise by himself and quiet conversations with one or two good friends. He would sometimes disparage the idle “blah-blah-blah,” as he would put it, of many Westerners. As we trekked and climbed for a month in the Khumbu Valley, it was obvious he felt at home with the early-to-bed, early-to-rise pace of Sherpa life.

Ueli’s last years followed a roller-coaster arc that don’t seem befitting of the guy I knew. In 2013, he was caught up in a tussle on Everest when his partner misused a Nepali epithet, upsetting a group of Sherpas. As if determined to move beyond the ugly incident, Ueli soloed the majestic south face of Annapurna a year later, a feat that earned him a second Piolet d’Or and seemed to cement his legacy. Then questions began to arise from certain peers—Ueli had dropped his camera during the ascent and didn’t have GPS tracking, and thus lacked empirical proof of the climb. Publicly, Ueli tried to shrug it off, but the fact that there would be a vague asterisk attached to the ascent must have eaten at him.

In between such intense efforts, Ueli found great joy in pleasure climbing with his wife, Nicole, visiting Patagonia, Nepal, Yosemite, and elsewhere with her on annual holidays. He learned to paraglide, wrote several books, and managed a brilliant enchainment close to home, climbing all the 4,000-meter peaks in the Alps one summer.

And yet death always seemed nearby. In 2014, two climbers he had teamed up with on Xixabangma died in an avalanche; in 2015, he lost a partner while completing the Alps project. As calculating a human as Ueli was, he would occasionally admit the odds were bound to catch up with him if he didn’t quit high-stakes soloing. “I think he would love to not go solo anymore,” said climbing partner David Göttler. “He liked the solo thing, because he could just concentrate on his own performance, but I had the impression that he really enjoyed being with a climbing partner. He just ended up being alone because no one could keep up with him.”

It is fitting that his closest companion on his last Himalayan climbs was a young Nepali friend, Tenjing Sherpa. After climbing Everest without oxygen with Tenji in 2012, Ueli invited him to Switzerland and encouraged him to pursue a career in guiding.

Before he embarked on his last expedition to Everest, Ueli mused to journalist Devon O’Neil about his fascination with the region: “Maybe I’ll just go back to the Khumbu my whole lifetime until I don’t climb anymore, because I see so many mountains and routes I still want to climb.”

After the fatal accident on Nuptse, Ueli Steck’s body was cremated at the Tengboche Monastery, in the heart of the Khumbu Valley.

– Freddie Wilkinson