Pre Alps

Heed trigger-sensitive snowdrifts

Heed trigger-sensitive snowdrifts

Fresh and older snowdrift accumulations are still trigger-sensitive on steep shady slopes, can in isolated cases be triggered by one sole skier. Danger zones occur esp. on shady steep ridgeline slopes, in gullies and bowls and behind abrupt discontinuities in the terrain above 2200m. Frequency of danger zones increases with ascending altitude. Especially in extremely steep terrain, loose-snow avalanche can trigger naturally due to warmth and solar radiation. Weak layer in the old snowpack can be triggered by large additional loading in isolated cases. Danger zones for these lie on steep W/N/E facing slopes above 2400 m and in transitions from shallow to deep snow. At intermediate and high altitudes on smooth, steep slopes, isolated glide-snow avalanches are still possible.

Nocturnal hours: widespread cloud layers above the summits, intermittent cloud cover. On Lake Constance and in the Rhine Valley, high fog up to 1300 m can spread. Temp: -4 to +1 degree. Thursday: weak high-pressure front conditions: sunny weather above the high fog (1300m), more clouds in the afternoon. At 2000 m: 0 degrees. Light to moderate E/SW winds.

On Friday, variably cloudy but dry. Danger of loose-snow avalanches will slowly decrease in the next few days. Snowdrifts on shady slopes are often poorly bonded with the old snow.