Bollettino valanghe

Wet-snow problem and high alpine weak layers in old snow

Wet-snow problem and high alpine weak layers in old snow

Predominantly favorable conditions and low danger prevail in the morning. Due to solar radiation and daytime warming, avalanche danger increases swiftly to moderate. Naturally triggered or low-additional-loading triggered small-to-medium wet-snow avalanches occur especially on E/S/W facing slopes up to high alpine regions and on shady slopes below 2400m. In regions where snowfall has been heavy on very steep grass-covered slopes, glide-snow avalanches continue to be possible. Caution below glide cracks. Weak layers in the old snow can often be triggered in high alpine regions, particularly by large additional loading small-to-medium avalanches can be triggered. Danger zones especially on very steep shady slopes.

A weak cold front brought a few showers yesterday, the snowfall level was at 2500m. Due to high air moisture and diffuse radiation the snowpack forfeited its firmness during the day and many wet-snow avalanches were reported. Last night temperatures dropped, clouds dispersed, a (breakable) melt-freeze crust formed. The thoroughly wet snowpack was able to consolidate in the near-surface layers. At low and intermediate altitudes there is not much snow on the ground. In high alpine regions, partricularly on very steep shady slopes, there are still isolated danger zones for dry-snow avalanches; small-to-medium slabs can trigger in the near-surface layers or at the Sahara dust layer.

Cold northerly air currents, but relatively good weather with sunshine and a few harmless cumulus clouds. It will probably remain dry, predominantly sunny this afternoon. At 2000 m: -1 degree. Moderate to brisk northerly winds at high altitude.

On Sunday and Monday it will be sunny following a night of clear skies. Favorable springtime conditions will reign in the morning hours, heightened danger of wet-snow avalanches in the course of the day.