Kilian Jornet, 25, one of the world's great endurance runners, has speed soloed the long, technical and exposed Innominata on the Italian side of Mont Blanc in a scant 6:17. The time is amazing on many levels. While technically the climb is easier than the north faces of the Eiger or the Matterhorn, the scale is much greater and the objective dangers are higher. Jornet, who is not even known as a climber, started from the church in Courmayeur at roughly 1000m and ran the 3600m to the summit of Mont Blanc, then ran over 3600m down the French side arriving at the church in Chamonix in a total time of 8:43.

Kilian Jornet © Suunto

He covered over 7,300m, climbing and running roughly 32km over glaciers, loose rock faces and miles of snow and ice slopes, all solo.

Jornet's astounding feat is, everything considered, on par with the recent Eiger speed ascents by Dani Arnold and Ueli Steck and fulfills the prophecy that the next level of technical speed climbers will come not from the world of climbing, but from ultra running. Ultra runners, it seems, can quickly learn to climb, while climbers are not so adept at ultra running, lacking the endurance. "Can you imagine what I could do if I had the physique of Kilian?" Steck told Rock and Ice.

Balancing act on the stunning snow arete of the Innominata- Mont Blanc S face. One of my favourite shots © Jon Griffith

Jornet, it should be noted, has one of the highest VO2 max levels ever recorded and has won the grueling Ultra Trail Mont Blanc (UTMB) three times and holds the speed record for running up the non-technical Mount Kilimanjaro (5:22). His speed solo of the Innominata is a huge leap beyond his previous achievements in terms of climbing difficulty and danger—a fast team typically bivies twice on the route, which is well known for its loose rock.

While Jornet is a new name to most American climbers, he is well know among runners. In 2011 he won the punishing 100-mile Western States Endurance Run and this year won the Pikes Peak Marathon and set the speed record for climbing and descending the Grand Teton. Also this year, in June, Jornet and Stephane Brosse attempted to cross the entire Mont Blanc Massif in two days when Brosse broke through a cornice and fell 600m to his death.