Steck died on 30 April 2017 while acclimatizing for an attempt of the Hornbein route on the West Ridge of Everest without supplemental oxygen. This route had been climbed only a few times, the last of which was in 1991. His plan was to climb the Hornbein Couloir to the summit, then proceed with a traverse to the peak of Lhotse, the world's fourth highest mountain. This combination had not been achieved.