Quote:Balanced on the edges of her skis on a steep, icy ledge on Canada’s Mount Robson, Christina Lustenberger picked her route down: all 3,000 meters (9,843 ft) of it. Sheer, exposed drops flanked each side of her, as she and her partner, Guillaume “Gee” Pierrel, prepared to descend an uncharted route on the mountain they had taken two days and two gruelling attempts to climb, through battering storms and bitter cold. Any misstep or wrong turn could prove deadly.

A ski prodigy from an early age, Lustenberger grew up hearing stories of adventurers who had climbed the imposing mountain, which, with an elevation of 12,970 feet is the tallest in the Canadian Rockies. Routes down Robson had been skied only a few times before, and the Great Couloir — a huge, steep snow gully that leads to the summit — on the mountain’s south face had never been attempted.