Persistent weak layers
- Above 2,400 m
- Taille
- 3
Stability: fair · Frequency: some
Weak layers in the old snowpack necessitate defensive route selection. Shady slopes where weaknesses exist in the old snowpack are especially precarious. As a consequence of warming during the day, the likelihood of moist avalanches being released will increase on south facing slopes below approximately 2600 m.
Stability: fair · Frequency: some
Stability: fair · Frequency: few
Weak layers in the old snowpack necessitate defensive route selection. Shady slopes where weaknesses exist in the old snowpack are especially precarious. As a consequence of warming during the day, the likelihood of moist avalanches being released will increase on south facing slopes below approximately 2600 m.
Weak layers in the old snowpack can still be released in some places by individual winter sport participants in particular above approximately 2400 m. This applies in particular in shady places that are protected from the wind. Avalanches can penetrate down to the ground and reach large size in isolated cases. As a consequence of warming during the day, the likelihood of moist and wet avalanches being released will increase on south facing slopes below approximately 2600 m. Avalanches can occur in particular in starting zones where no previous releases have taken place.
Towards its surface, the snowpack is hard and its surface has a crust that is strong in many cases. Towards its base, the snowpack is faceted and weak. Avalanches can be released in deeper layers also. In addition the fresh wind slabs adjacent to ridgelines and in gullies and bowls are easily triggered. The surface of the snowpack has frozen to form a strong crust and will soften quickly. This applies in particular on sunny slopes below approximately 2600 m.
As a consequence of warming during the day the prevalence of the avalanche prone locations will increase as the day progresses.
Bulletin data: ARPA Lombardia (via EAWS / avalanche.report)