The Vallée Blanche is the most famous off-piste ski run in the world and one of the great mountain experiences in Europe. Starting from the Aiguille du Midi at 3,842 metres, it descends 24 kilometres across the upper Mer de Glace glacier to arrive back in Chamonix — a drop of 2,800 metres. On a clear winter's day, the route takes you past seracs, crevasse fields, and the full sweep of the Mont Blanc massif in absolute silence.
The run is not technically difficult by off-piste standards, but it is not a piste and must be done with a certified mountain guide. Route-finding across the glacier requires knowledge of current crevasse positions, which change each season. Guides lead groups of up to four or five from the Aiguille du Midi cable car, navigating the knife-edge arête walk at the start and plotting a safe line across the glacier. Allow a full day. In summer, the same route can be walked or run as a glacier trek.