Weisseck, Muhr Valley

Daytime loss of snowpack firmness and high-alpine snowdrifts

Daytime loss of snowpack firmness and high-alpine snowdrifts

Avalanche danger above 2300m is MODERATE, otherwise LOW in early morning, then rising to MODERATE by midday. Avalanche prone locations for slab avalanches occur at high altitudes in NW/N/E aspects, in high alpine regions also in southern aspects on steep slopes. Particularly in shady terrain, even minimum additional loading is sufficient to release a small-to-medium slab avalanche. Danger zones are near to ridges and in wind-loaded gullies and bowls. Naturally triggered wet loose-snow avalanches (also from addtional loading) are possible in sun-drenched steep terrain and isolated glide-snow avalanxches in extremely steep grassy terrain. These can reach medium size, in isolated cases large size.

Fresh snow and drifts from the weekend have settled well, the snowpack is thoroughly wet up to 2600 m. The proneness to triggering (E/S) has receded. Steep sunny slopes have a melt-freeze crust capable of bearing loads in early morning, then softening up quickly during the daytime, depending on aspect and altitude. The smooth layer containing Sahara dust has the greatest potential to become a weak layer; however, isolated releases have fractured deeper down still inside the snowpack.

On Thursday, following a night of good outgoing longwave radiation, sunny weather to start with, and some high-altitude clouds. In the afternoon cloud cover will become denser, convective cloud build-up can be expected, isolated showers are then likelier. Winds from the north will be moderate to brisk. At 2000 m: 8 degrees, at 3000m: +2 degrees. Thursday night skies will be overcast, rainfall up to the summit regions is expected. On Friday, repeated bouts of rainfall, often reduced visibility, punctuated by brighter interims, although only brief ones. The NW winds light to start with, intensifying a little as of midday. At 2000 m: 3 degrees, at 3000 m: -3 degrees.

No cold reserves in the snowpack on Friday. Bad day for backcountry tours. MODERATE danger of avalanches right from the start.