At the end of the season, high temperatures often occur, especially in the middle of the day. With high temperatures, snow crystals melt and the layers of snow become more and more moist, forming an inner source of melted snow. If this meets a hard and inpenetrable layer of snow, it spreads itself over this layer and creates a slide, down which an avalanche can move. The same thing happens when it rains. This type of avalanche can be launched on a slope with a gradient of only 20°. In the worst case, the layer of snow can become so soaked that the earth itself or the rocks below can themselves become the slide that launches an avalanche.