Lechquellen Mountains

Weakening snowpack due to rain - Heed fresh snowdrift accumulations at high altitudes

Weakening snowpack due to rain - Heed fresh snowdrift accumulations at high altitudes

At high altitudes avalanche danger is considerable, otherwise danger is predominantly low-to-moderate. Fresh snowdrift accumulations lie deposited mostly on steep shady slopes and are easy to trigger. Danger zones occur behind abrupt discontinuities in the terrain and in wind-loaded gullies and bowls, they tend to increase in frequency with ascending altitude. Weak layers in the old snow can be triggered mostly by large additional loading, they are most likely to occur on very steep W/N/E facing slopes above 2200 m and in transitions form shallow to deep snow. In zones where there has been rain impact, slides and small wet snow avalanches can be expected.

On high-altitude shady slopes there is still powder or surface hoar. On south-facing slopes there is a melt-freeze crust or wind crusts. Fresh snow and drifts are poorly bonded with each other and the old snowpack, and bonding worsens with ascending altitude. Particularly on very steep shady slopes there are unfavourable intermediate layers inside the snowpack. With warmth, the snowpack is weakened. Rainfall causes it to forfeit its firmness. Artificial triggerings have shown much success, triggering medium-to-large size avalanche releases.

Rain and snow showers will extend into the afternoon, though slackening off. Snowfall level at 1500-1800m, thereafter clouds will begin to disperse, visibility improve, it will become sunny. At 2000m: +1 degree; strong to stormy westerly winds, later easing.

Friday will bring more serene conditions. Avalanche danger levels could increase due to fresh snow and wind.