Bulletin d’avalanche

Daytime cycle of wet-snow avalanches, continuing glide-snow avalanches, older snowdrifts at high altitudes often still prone to triggering.

Daytime cycle of wet-snow avalanches, continuing glide-snow avalanches, older snowdrifts at high altitudes often still prone to triggering.

On sunny slopes below 2400 m (and shady slopes below 2000 m on steep grassy slopes, in forest clearances and on hillsides, increasingly frequent small-to-medium glide-snow avalanches can be expected. In regions where snowfall was heaviest they can grow to large size in isolated cases. Cracks in the snowpack are red flags of approaching danger. On sunny slopes, in addition, superficial wet loose-snow and slab avalanches can trigger naturally during the course of the day. Older drifts become more prone to triggering with ascending altitude and can be triggered, particularly by large additional loading. Avalanche prone locations are found especially above 2200 m, in steep ridgeline terrain, in wind-loaded gullies and bowls. At very high altitude and in high alpine regions the situation is more treacherous. In addition, on high-altitude shady slopes, ground-level weak layers can be triggered particularly by large additional loading in transition zones from deep to shallow snow. If avalanches fracture down to deeper layers of the snowpack they can easily grow to large size. A cautious route selection is recommended.

Due to higher temperatures, the moist snowpack has regained some firmness during the nights when it cools down, is now melt-freeze encrusted on the surface. This crust softens during the daytime, the snowpack again forfeits its firmness. Some rainfall up to high altitudes on Monday generated a thin, breakable crust. Below about 1800 m the old snowpack has settled well but is moist, which furthers the gliding movement of the snow cover over smooth ground. Due to persistently higher temperatures the gliding of the snowpack continutes at a high level. Older snowdrift accumulations frequently become more prone to triggering with ascending altitude. Due to significantly higher temperatures the snowdrifts generated last week are settling and consolidating to an increasing degree. At mid-level inside the snowpack on high-altitude shady slopes, faceted-crystal weak layers are evident, especially in the vicinity of crusts.

High-pressure front conditions are increasing. Sunshine from early until late, often from cloudless skies. The fog at the rim of the Alps extends up to neaerly 1000 m and will persist all day long. Temperature at 2000 m: +2 degrees. Moderate to brisk N/NE winds at high altitude.

Avalanche danger levels will not change significantly. The danger of dry-snow avalanches will continue to recede. The danger of wet-snow avalanches will increase in the course of each day. Glide-snow avalanches continue to be expected.