The course used in each event is loosely specified, every competitor must pick his preferred route between fixed start and finish points, selecting a line that will best show the judges their imagination, nerve, showmanship and athleticism.

'Bib' numbers are allocated to competitors and these can alter performance a good deal, with early numbers encountering great clouds of 'sluff' as high drifts of loose snow demolish on first contact, obstructing the route.

The best-chosen line will allow the rider a slick but spectacular passage, including daunting cliff-jumps, negotiating perilous rocky outcrops, using and controlling the effect of soft, deep virgin snow and leaving time to demonstrate tricks of handling.

The wild scenery and the hazards of a snowbound mountain zone provide plenty of opportunities to impress the judges and thrill the crowds.

Recovery from death-defying drops, rapid traverses, amazing balance and sudden speed, highlight the unflappable skill of competitors like Flo Orley and Aurelien Ducroz, aiming for the $250,000 first prize.