Avalanche Forecast

Moderate -

TUESDAY NIGHT: Cloudy with isolated flurries, accumulation up to 5 cm. Moderate west wind. Freezing level 1000 mWEDNESDAY: Cloudy with isolated flurries, accumulation up to 5 cm. Moderate gusting strong west-southwest wind. Freezing level 1200 m.THURSDAY: Snow, 10-25 cm new snow, increasing through the day. Moderate southwest wind. Freezing level 1300 m.FRIDAY: Mix of sun and cloud. Moderate west wind with occasional strong gusts. Freezing level valley bottom.

Extensive recent avalanche activity has occurred in the Purcells since December 12. Explosives triggered avalanches to size 3 on Monday and although natural avalanche activity has started to subside, human-triggered avalanches remain a concern. On Sunday, a small sluff triggered by a skier stepped down to a deeply buried weak layer (likely basal facets) causing a size 2 avalanche. Another very notable avalanche occurred on Saturday when a size 2.5 avalanche was remotely triggered from 50-100 m away on a northwest aspect at 2250 m. A report of this avalanche can be found on the Mountain Information Network. (here)

Approximately 60-120 cm of recent snow sits on a weak layer of facets (sugary snow), surface hoar (feathery crystals), and a sun crust (on south facing slopes). Strong winds have promoted widespread slab formation.Another layer of surface hoar and sun crust is now buried 80-150 cm. The potential may exist for smaller avalanches to step down to this deeper layer, resulting in very large avalanches. The most likely areas for this layer to be a problem is where the surface hoar sits on the sun crust, which is most likely on steep south facing terrain at treeline.At the base of the snowpack is a crust that formed in late October. This layer is likely only a problem on large, steep alpine features with a shallow snowpack. It would likely take a large trigger, such as a cornice fall, to produce an avalanche on this layer.