Ultra-Trail du Mont-Blanc (UTMB)

Circumnavigation of Mont Blanc through France, Italy, and Switzerland. 32,800 ft of elevation gain. Rocky alpine terrain, high passes, and narrow trails.

Late August in the Alps: highly variable — can be warm in valleys, cold and snowy at altitude. Night temperatures at high passes drop below freezing. Weather cancellations are not rare.

Life bases (full resupply) at Courmayeur, Champex-Lac, Trient, and Vallorcine. 36 aid stations total with French, Italian, and Swiss food spread.

Altitude (multiple passes above 8,000 ft) suppresses appetite and digestion. Athletes at the Courmayeur life base (mile 50) are already severely depleted and have 56 miles left.