SoCal does not experience avalanches very often.  Since 1950, at least 64 people have died in avalanches in California with 9 of those in SoCal, according to this article.

Snow avalanches can cause a significant loss of life. As a naturally occurring disaster they are unique in nature, usually being highly localized events, and often in remote areas. Their victims are often voluntarily at risk for recreation purposes and become the trigger of their own avalanche.

Avalanche forecasting seeks to safeguard recreationists in winter mountain environments using risk based decision making.  Avalanche experts interpret the spatial and temporal distribution of hazards and abstractly present these in the form of a forecast.  Recreationists can then use them for planning excursions into avalanche prone terrain and avoid high risk slopes that pose a hazard.

Check out this article on how Scotland looked at using GIS to make cartographic visualizations of predicted avalanche danger areas.