Ice and cornice fall avalanches

When glaciers flow over a cliff they form the ice equivalent of a waterfall—an icefall. Falling blocks of ice can trigger an avalanche of ice, which often entrains snow below it, or triggers slabs. Especially in big mountains, ice avalanches can be large and travel long distances.

Despite this, ice avalanches kill few people compared to dry slabs that people trigger themselves. Most of the deaths from ice avalanches occur to climbers in big mountains who happen to be in the wrong place at the wrong time.

Cornice fall avalanches
Cornices are the fatal attraction of the mountains, their beauty matched only by their danger. Cornices are elegant, cantilevered snow structures formed by wind drifting snow on to the lee (downwind) side of an obstacle, such as a ridgeline. Similar to icefall avalanches, the weight of a falling cornice often triggers an avalanche on the slope below, or the cornice breaks into hundreds of pieces and forms its own avalanche—or both.

Again like ice avalanches, statistically cornice fall avalanches don’t kill very many people. And similar to slab avalanches, the skiers who get into trouble almost always trigger the avalanche, in this case by traveling too close to the edge of the cornice. Cornices have a nasty habit of breaking farther back than you expect. Never walk up to the edge of a drop-off without wearing a rope or first checking out the drop-off from a safe place.