Nock Mountains

Surface triggered wind slab snow can activate persistent weak layer problem

Surface triggered wind slab snow can activate persistent weak layer problem

The avalanche risk increases rapidly with altitude from the tree line and is considerable above around 2000 metres. The situation remains precarious for winter sports. Medium-sized slab avalanches can easily be triggered by individuals in some places, especially from north-west to north to east. There is a high likelihood that surface-triggered avalanches will tear through to deeper layers. Danger areas are barely recognisable and require a defensive choice of route. Take particular care near transitions from little to much snow and in the entrance areas to steep gullies.

New and wind slab snow cover a very different surface: in exposed areas it is marked by the wind, otherwise it is partly encrusted and hard, but also partly still soft. On shady slopes protected from the wind above around 1500 m, surface hoar is also covered with snow in places. Fresh and older/hard wind slabs overlay soft layers of faceted crystals and deep rime. In general, zones with little snow and considerable areas of drift snow are often close together. Breaks occur either in soft layers near the surface or around the crust that forms the transition to the completely angular old snowpack. The total snow depth is well below average.

In the evening and on Friday night, strong to stormy winds from the west to northwest will bring a few to a maximum of 10 cm of new fallen snow (in the west), snowfall level around 1100 metres. Hardly any snow will fall during the day. The wind will still be strong at first, but will ease during the morning and the clouds will soften again from the west. At 2000 m -5 degrees, at 3000 m -12 degrees.

Little change at first on Saturday, with new fallen snow and wind exacerbating the wind slab problem towards the evening.