How do avalanches occur?
Avalanches can only occur on slopes steeper than about 25 degrees, and they are most common on slopes between 35 and 45 degrees. This is because slopes less than 25 degrees are typically not steep enough to slide, and slopes greater than 45 or 50 degrees tend to sluff snow constantly, which prevent large slabs from avalanching. Determining factors of whether a slope can slide are the steepness of the slope, its aspect (which direction it faces), the slopes shape, and its natural features. Steepness is the most important factor to consider. Most skiers and snowboarders tend to recreate on slopes between 30-40 degrees, where avalanches are most prone. Diagram of how avalanches occur.
