Lechquellen Mountains

Beware snowdrifts and weak layers on shady slopes

Beware snowdrifts and weak layers on shady slopes

Fresh snow and drifts on wind-protected shady slopes often lie deposited atop surface hoar. Winter sports enthusiasts can trigger avalanches. In addition, isolated avalanches can be triggered in the weak old snow, particularly by large additional loading in shady, very steep backcountry touring terrain. These danger zones occur most of all in steep spots where the snow is relatively shallow and in transition from shallow to deep snow. If avalanches fracture down to deeper-down layers inside the snowpack, they can in isolated cases grow to large size.

Above about 1500m there was about 10cm of fresh snow registered on Thursday, less in Silvretta and Verwall. Fresh fallen snow and loosely-packed old snow will be transportred by intensifying foehn winds until Saturday midday. Thereafter, another 5-10cm of fresh snow will be added to it. The fresh fallen snow frequently lies atop surface hoar on shady slopes at all altitudes. The mid-part of the snowpack consists widespread of well settled, compact layers which on shady high-altitude slopes blanket a poorly structured old snowpack fundament.

On Saturday it will remain dry through most of the morning hours, accompanied by final foehn-generated bright intervals. Then skies will cloud over, before midday the first precipitation will begin, becoming heavier in the afternoon. Snowfall level will drop from 1500m down to 1000m by evening. Temperatures at 2000m: initially at 0 degrees, in the afternoon dropping successively down to -6 degrees by the end of the day; at 3000m: from -6 to -11 degrees. At high altitudes, initially brisk southwesterly winds, blowing at strong velocity in gusts, later shifting to northwesterly and blowing at moderate velocity.

By Sunday, 15-25cm of fresh snow is anticipated. Accompanied by moderate-strength winds, generally small snowdrift accumulations can be generated near ridgelines at higher altitudes.