Boletín de aludes

Caution urged towards fresh snowdrifts and weak layers in old snow

Caution urged towards fresh snowdrifts and weak layers in old snow

Southerly foehn winds are generating small, trigger-sensitive snowdrift accumulations which can be triggered even by the weight of one sole skier but generally remain small sized. Weak layers can be triggered by large additional loading, e.g. a group without distances, on W/N/E-facing slopes, particularly above 2000 m in transitions from shallow to deep snow, e.g. at entries into gullies and bowls. Triggered avalanches can grow to large size. In steep rocky terrain, small superficial loose-snow avalanches can release due to solar radiation and daytime warming. Glide-snow avalanches possible on steep grassy slopes.

Pronounced weak layers are evident at mid-level inside the snowpack. They are prone to triggering on W/N/E-facing slopes and very difficult to evaluate. Where these layers are covered over by thick fresher layer they are no longer a threat. In Rätikon and Verwall and Silvretta, the covering is shallower, thus they can be triggered, particularly in transition zones from shallow to deep snow. Avalanches can fracture down to deeper layers and then grow to large size. As a result of strong foehn wind, fresh trigger-sensitive snowdrifts will be generated on shady slopes in particular. At high altitudes the snowpack surface shows heavy effects of wind, only on shady slopes and in wind-protected terrain is the snow still loose. During the course of the day the melt freeze crust will soften on sunny slopes. On crests are often powerful, leaning cornices which require attentiveness.

Sunshine again, little wind, the beautiful weather will persist into the afternoon, then clouds will gradually move in above summit level, the southerly winds intensify by evening. During the night, snowfall and a cold front, the wind will shift from southerly to northwesterly. Temperature at 2000 m: -6 to 0 degrees. Noticeably dropping temperatures On Monday night. Moderate southerly winds at high altitudes.

Monday night, snowfall will set in above 800 m. Tuesday morning, persistent snowfall. Moderate to brisk NW winds will be blowing. Avalanche danger will increase widespread.