Bollettino valanghe

Weakly bonded old snow on very steep shady slopes.

Weakly bonded old snow on very steep shady slopes.

Weak layers in the old snowpack can be released in isolated cases and mostly by large additional loads at transitions from a shallow to a deep snowpack, when entering gullies and bowls for example. The avalanches can be released in deep layers of the snowpack and reach medium size. The older wind slabs can be released, especially by large additional loads, on steep shady slopes above approximately 2300 m. The avalanche prone locations are rather rare but are easy to recognise, caution is to be exercised in particular at transitions from a shallow to a deep snowpack, when entering gullies and bowls for example. The conditions will facilitate a gradual strengthening of the snow drift accumulations in all aspects.

The snowpack will be subject to considerable local variations. At a distance from ridgelines and in shady places that are protected from the wind: Towards its surface, the snowpack is soft and its surface consists of loosely bonded snow lying on a strong melt-freeze crust. Sunny slopes: Towards its surface, the snowpack is largely stable and its surface has a strong crust. This also applies at high altitude. Faceted weak layers exist in the snowpack on shady slopes. The older wind slabs are to be found especially in gullies and bowls, and behind abrupt changes in the terrain.