Lac de Chéserys in the Aiguilles Rouges above Chamonix offers spectacular views of the Mont Blanc massif. At the end of a stormy day, the setting sun dramatically illuminated foehn clouds, signaling strong winds at high elevations. Yet for a fleeting moment, the wind calmed just enough to allow the snowy mountain range to be reflected in the glassy surface of this beautiful alpine lake.
The rainy and chilly Central European summer of 2011 was caused by a stationary trough over the region. The upper-level air current in the midlatitudes normally moves slowly from west to east, meandering around the globe. A blocking pattern brought this movement to a standstill, leaving the trough anchored over Central Europe. Numerous low-pressure systems developed within it, carrying cold, cloudy air that originated in polar regions. The southern boundary of the trough was often situated around the Southern Alps, producing constantly changing weather as fronts and weak high-pressure ridges moved through the region.
Orographic foehn clouds frequently formed over the mountains when strong winds developed at high elevations, often heralding the arrival of rainy weather. Cold fronts triggered thunderstorms with intense convective rainfall in the valleys and large amounts of snow on the jagged peaks. Such unstable weather creates dramatic cloud formations but also frustrates the desired lake reflections because of the strong winds. In addition, the abundant moisture often concealed the 15,781-foot (4,810-meter) Mont Blanc massif beneath convective clouds.
It took considerable time, careful weather forecasting, and a strenuous journey to reach this remote lake at precisely the right moment: when the snowy massif emerged from the clouds in the fading light and the wind dropped enough to create a perfect reflection in the lake.
