All of the information we use to predict snow stability is in this triangle. Learn to recognize the subtleties of avalanche terrain. Most mountain travelers can spot the obvious paths. But learning to anticipate where on a particular slope that a fracture will occur, and how far it may propagate, takes some study. Learn to pay attention to the weather.
Storms are the source of most the world's avalanches.
The combination of new snowfall and wind creates the unstable layering that result in slab avalanches. Simply put, during a storm, the rate at which stress is added to the snowpack exceeds the rate at which these new layers can gain strength. A prolonged period of cold and clear weather can substantially weaken the snowpack. This can set up a hair trigger situation. Qualities like the stiffness or styro-foam texture of the snowcover are significant.