Persistent weak layers
- Above treeline
Older wind slab lies on top of a weak persistent weak layer.
Older wind slab lies on top of a weak persistent weak layer.
The avalanche risk is moderate above the tree line and low below it. Persistent weak layers are problematic. In some places, old snowdrift accumulations can be triggered as a slab avalanche by even a small additional load in very steep terrain in the north-west to north to south-east aspects. The number and size of avalanche prone locations increase with altitude. Avalanches can reach medium size if deeper, weak layers are also triggered.
Older snowdrift accumulations lie on soft layers or on a melt-freeze crust, under which angular crystals can be found in places. The old snowpack usually consists of faceted crystals with rounded edges and is partly interspersed with melt-freeze crusts. A thin melt-freeze crust forms on the surface on the sunny slopes overnight. Overall, there is little snow.
Slight increase in avalanche danger with new fallen snow and wind.
Bulletin data: Avalanche Warning Service Bavaria (CC BY 4.0)