Anatomy of a slab avalanche
An avalanche is the sum of three parts: the start zone at the top, the track down which the avalanche accelerates and the run out or deposition zone where the avalanche stops.
start zones
The start zone is the most volatile area of a slope where unstable snow can fracture from the surrounding snow cover and begin to slide. Some typical start zone features are: an angle of around 37 degrees, lee to the wind, convexities or pillows of snow, directly below a cornice, by rocks or shallow snow . . .
path or track
Unlike tornadoes, shark attacks or lightening strikes, avalanches do not touch down randomly but occur in fixed locations known as avalanche paths. The chief factor that determines whether a slope can avalanche is its angle. Read more about slope angles in the next section.
Avalanche paths in North America with a history of threatening people or property earn names for themselves. Valerie's climax earned its moniker when Valerie and the man with whom she was having an affair defied orders to evacuate employee housing while avalanches were being shot down. After an avalanche ran through Valerie's house, the lovers had to be rescued naked from her crushed bedroom.
(Fredston 2005).
runout zone
The runout zone is where the snow and debris pile the highest and where a victim will most likely be buried.