Avalanche Forecast

Fair - Intensity of incoming weather systems is uncertain

A succession of storms progressively get stronger and warmer through the weekend.  Friday: flurries in the afternoon. Freezing levels 1000 m in the morning, climbing rapidly towards 2000 m in the afternoon. Ridgetop winds 30-40 km/h from the southwest.  Saturday: Rain to all but the highest areas. 5-10 mm is the best current estimate. Freezing levels around 2400 m. Strong southwesterly winds.  Sunday: Light rain. Models currently indicate around 5 mm. Freezing levels around 2500 m. Strong southwesterly winds.

Avalanches up to size 2 were reported to have run during and immediately after the most recent storm on all aspects and at elevations from 1800-2300 m. Most avalanches were running on the most recent layer of surface hoar, with typical crown depths of 30-60 cm. There was one report of an avalanche on the more deeply buried mid-December weak layer, although it appears as though it may have been triggered in a shallow spot, as the crown depth was reported to be only 30-45 cm.

Between 15cm and 40cm of recent snowfall fell during the last major storm last weekend. Wind slab deposits have been consistently reported in alpine areas. This new snow buried a prominent layer of surface hoar, which sits above a sun crust on steep sun-exposed slopes. This "mid-January" weak layer has been responsible for most of the recent avalanche activity. Reports do indicate that this layer is starting to gain some strength in this region, becoming more difficult to trigger when ski-cutting small slopes.The mid-December surface hoar/crust layer is typically down 60-120cm below the surface. The reactivity of this persistent weak layer appears to be quite variable but the potential still exists for large, destructive avalanches in some areas. The layer appears to be the most reactive at and below treeline. The mid-Nov weak layer comprising facets can still be found near the bottom of the snowpack but has generally become inactive.