Nock Mountains

Caution on very steep, shallow-snow slopes and on steep ridgeline slopes.

Caution on very steep, shallow-snow slopes and on steep ridgeline slopes.

Avalanche danger above 1500 m is MODERATE, below that altitude danger is LOW. Two moderate problems: persistent weak layer – this is the dominant theme of the moment, though hardly detectable from the snowpack surface. Potential weak layers inside the snowpack are likeliest in transitions into wind-loaded zones (often where snow is shallow). All in all the terrain has few spots where large additional loading (a fall, a group without distances, stomping) can trigger a slab avalanche. But if a slab triggers it can grow to large size. Second problem: snowdrift threat – the fresh drift are small and thin. On steep slopes they can trigger a small avalanche. In extremely steep terrain they can be triggered by a fall.

The latest fresh snow was transported somewhat by southerly winds, small snowdrift accumulations were generated, mostly thin and not extensive. Atop those, a new layer which is being transported by NW winds in ridgeline zones. Beneath the new snow are compact layers with the dynamic forces well distributed. Inside the snowpack, particularly on north-facing slopes, are faceted crystal weak layers which could tend towards fracture propagation.

On Tuesday, dense cloud cover with snowfall will move in, visibility will deteriorate swiftly. Fresh snow in 24 hours: 5-10 cm. Winds will shift to NW and reach 30 km/hr. At 2000 m: -5 degrees, at 3000 m -11 degrees. On Wednesday, adequate visibility to start with, a brief interim of sunshine, then cloud will move in, summits disappear in fog. Later in the afternoon/evening the next round of precipitation will arrive with strong-to-stormy westerly winds. Snowfall level: 1500 m. At 2000 m: from -4 to 0 degrees; at 3000 m: -9 to -4 degrees.

On Wednesday night, stormy winds and warm fresh snow or rain. Thus, the overall situation will change. Danger level: moderate (2) or considerable (3) due to wet snow / glide-snow problem. Snowdrift problem: see above.