Cornice

The build-up of a snow on the lee side of a slope, ridge, escarpment or cliff. The cornice is like a wave of snow protruding out over the edge of the rock due to the action of the prevailing wind. Cornices can protrude beyond the rock by many feet and are often unstable. This is the reason that you don’t walk too close to the edge for fear of falling through the cornice – many people have done so, and the consequences are generally not pleasant – especially on the north face of Ben Nevis. They can be challenging to overcome when climbing or descending and often require you to “cut a hole or passage through them” with your ice axe first, before trying to cross the lip or edge.