In the Northern hemisphere more than 60% of fatal avalanches occur on the northwest to east facing slopes of the mountains. The major weather systems in Europe and the western United States and Canada come form the west, resulting in the biggest snow masses accumulating on northeast to southeast facing slopes. At the same time north to east facing slopes receive little, if any, sun, meaning that the snow has difficulty in sticking onto the surface and therefore is more prone to slide easily.

In the Southern hemisphere the conditions are the reverse with the western and southern slopes being the most dangerous.