Nock Mountains

Moisture penetrates into poor persistent weak layers

Moisture penetrates into poor persistent weak layers

The avalanche risk is considerable above the tree line. Below this, it is low in the morning and quickly increases to moderate danger everywhere due to heat and radiation. Above the tree line, medium and sometimes large dry slab avalanches can easily be triggered by people in some places. All aspects are affected, but increasingly the north-east sector. Danger areas are difficult to recognise away from obvious pillows of wind drifted snow, which is why caution and a defensive choice of route is still advised. This applies in particular in the area of the tree line and in forest aisles. As the snowpack softens, spontaneous wet loose snow and gliding avalanches are to be expected on the sunny slopes, including in the northern sector at low to medium elevations. It is also possible for skiers to release wet snow slabs. Loose snow slides can easily tear through the drift and persistent weak layer and reach dangerous sizes.

The upper part of the snowpack is made up of several layers of new fallen snow from the last week, which was influenced by the wind. Where there was a significant old snowpack before the snowfall, the foundation has been completely transformed and is cohesionless. Fractures primarily occur between the last snow packs, but can penetrate through to this deep snow pack under greater load. During the night, a mostly stable melt cover forms, which softens quickly during the day with the heat. In some places, isothermal conditions are already reached.

The night is dry and starry, and the wind should not be an issue. Excellent visibility and plenty of sunshine on Thursday, with a few high clouds making themselves felt from time to time. The wind will be rather weak and mostly below freight strength. At 2000 metres it will be quite mild with temperatures between 4 and 6 degrees, at 3000 metres around -1 or 0 degrees.

Only a slow decline in the risk due to poor old snow cover.