Bollettino valanghe

Fresh snow and snowdrifts prone to triggering with ascending altitude

Fresh snow and snowdrifts prone to triggering with ascending altitude

Above 1800 m avalanche danger is considerable, below that altitude danger is moderate. As a result of fresh snow and moderate-strength northerly wind, fresh snowdrift accumulations have been generated in exposed terrain. Fresh snow and drifts are increasingly prone to triggering with ascending altitude, avalanches can be triggered even by one sole skier and grow to medium size. Frequency and size of avalanche prone locations increase with ascending altitude, particularly in ridge zones in all aspects, on very steep high-altitude slopes and in high alpine regions. Activities in outlying terrain require experience in assessing avalanche risks on-site. Isolated glide-snow avalanches are also possible. Caution is urged below glide cracks.

Persistent snowfall yesterday morning, showers in the afternoon and during the night. The amounts were modest: up to 15 cm widespread, more from place to place. In the Bregenzerwald mountains bordering the Rhine valley and Silvretta there was 30 cm. Since Wednesday there has been 30-40 cm of fresh snow registered widespread, in the Bregenzerwald mountains bordering the Rhine valley and Silvretta as much as 50-60 cm. It was deposited atop a raw old snowpack surface, is generally well bonded with it. In high alpine regions, bonding is poorer, avalanches can generally trigger only inside the layers of fresh snow and drifts from this period, in high alpine regions also at the borderline to the old snowpack. The old snowpack at intermediate altitudes is thoroughly wet, and it is wet up to high altitudes on sunny slopes, furthering the gliding movement of the snowpack on very steep and smooth slopes. At intermediate altitudes the sunny slopes are mostly bare of snow.

The northerly air current will remain icy cold, light to moderate snowfall, not much wind. In the barrier cloud regions of Bregenzerwald to Arlberg, heavier and more frequent snowfall than in Rätikon and Silvretta. Clouds and fog will create poor visibility. At 2000 m: -10 degrees. Light northerly winds at high altitude.

On Sunday conditions will settle except for a few snowflakes, with less cloud cover. In case of solar radiation, loose-snow avalanches are possible on sunny slopes. Avalanche danger is not expected to change significantly, it will recede at the beginning of next week.