When the snow that lies on the southern and western slopes warms up towards the afternoon and begins to melt, the stability of the upper layers of the packed snow behind to weaken. The snow becomes heavier and the small bridges of ice that are held together by ice crystals begin to melt. If the layer of snow is put under enough pressure, by a skier for example, it shatters and releases itself in the form of an avalanche.

If it becomes cold again after the snow has been warmed up, the bridges of ice freeze again and the snow becomes stable. As the ski season progresses so does the risk of an avalanche occurring earlier in the day. Towards the end of the season you should avoid skiing on southerly and westerly slopes all together.