Obituary: Ueli Steck, at summit of solo mountaineering

Ueli Steck, who has died at the age of 40, was arguably the greatest mountain climber of his generation. The extraordinary feats of the man known as "the Swiss Machine" included solo speed ascents of the 1600m north face of the Eiger and solo ascents without bottled oxygen of Himalayan giants.

The north face of the Eiger holds an almost mythical appeal for climbers due to the legend behind its first ascent in 1938, when two parties from Austria and Germany took four days to climb through its sections of rock, snowfields and ice while battling constant rock falls, storms, thirst and hunger.

Almost all previous attempts had ended in tragedy and death.

Steck's fascination with the Eiger's north face began when he was 18, when he climbed it for the first time. In 2001, he and partner Stephan Siegrist climbed a new route and three years later the pair climbed the three north faces of the Mönch, the Eiger, and the Jungfrau in one 25-hour push.

In 2007 Steck decided to see how fast he could climb the original route on the Eiger. His time of three hours 54 minutes broke the record but he returned the following year, determined to go faster. He brought the time down to two hours 47 minutes.

He returned in 2015, at the age of 39, to do it in two hours 22 minutes.

Steck trained with Swiss efficiency, employing a coach and physical therapist from Switzerland's top Olympic facility. He would spend up to 30 hours a week running, climbing, cross-country skiing and strength training.

This professional approach, unusual among climbers, translated into his ascents. Thirty-nine minutes into his 2008 climb, he paused to lower his heart rate and increase his co-ordination, and thus climb faster. He climbed the next 54m in four minutes.

His range of ascents encompassed Alpine climbs of the highest technical difficulty and solo ascents of Himalayan giants, and he climbed six of the 14 mountains over 8,000m, including Mount Everest, without bottled oxygen.

"It's out of the question for me to use bottled oxygen," he once said.

"I either make the summit without it or I turn back, go home and train more."

In 2014 he received a Piolet d'Or, the highest honour in climbing (for the second time), after making an incredibly bold solo ascent the previous year of the south face of Annapurna, 8,091m, which was regarded as one of the most significant ascents in the Himalayas in a generation.

Steck climbed it, alone, in 28 hours. "I was at the limits of my physical and mental ability," Steck said afterwards. "If I climb anything harder than that I think I will kill myself."

Steck was born on October 4 1976 in Ringgenberg in the canton of Bern, the youngest of three brothers. His father was a coppersmith and he grew up in the Emmental, an idyllic valley north of Interlaken.

When he was 12, a friend of his father's took him on his first climb.

In 2015, after many expeditions in the greater ranges, Steck decided to get back to his roots and spend the summer enjoying classic Alpine climbs in a way only he could; he climbed all 82 of the Alps' 4,000m peaks in 62 days, travelling to them by bicycle.

He died on April 29 during the acclimatising phase of an attempt to climb a new route on Everest.

"Mountaineering is a transient experience. I need to continuously repeat it to live it," Steck once said.

He is survived by his wife, Nicole. There were no children of the marriage.

1976-2017