"Most of the avalanches catching people are triggered by people"

A small slab avalanche. Small, but potentially serious.

Not all avalanches are the thundering ones you've seen on TV. A slab avalanche, shown here (left) is easily triggered by a skier, given the right conditions. The weight of a person can cause a slab of snow to fracture from the snowpack above it along the clean line you see across the hill. The person invariably ends up in the slide path and can easily be buried under the snow, which typically resembles concrete after the slide. Skiers have a big responsibility to themselves and their party when they are in avalanche terrain. If you're unfamiliar with avalanches, I recommend some of these links: Avalanche Primer (A 2-minute read from the Oct '98 issue of Rock Talk) Avalanche Formation and Release a great 3-page introduction.