Avalanche Forecast
Issued: Nov 23rd, 2012 9:22AM
The alpine rating is Persistent Slabs and Wind Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Poor - Due to limited field observations
Weather Forecast
The storm that arrived overnight Thursday moved out of the region Friday. Incoming air is looking cooler and drier. Precipitation: no significant snow or rain forecast through Monday. Wind: light SE Saturday veering to light NW Sunday and backing to the West on Monday. Temperature: cooling with below freezing temperatures at all elevations overnight and around 800m or 900 m during the day. Alpine temperatures around -5 to -10C. You're likely to see at least some sun this weekend, more likely on Sunday.
Avalanche Summary
Previous to Friday's storm, isolated size 2 avalanches were reported running on the early November crust. No reports from the region following Friday's storm. There was likely enough snow, when combined with strong winds, that natural avalanches released (wind slabs behind ridges?). My suspicion is that natural storm snow avalanches have now ended but the possibility of triggering a lingering pocket remains this weekend.
Snowpack Summary
No field reports since Friday's storm, however weather stations show enough new snow (15 cm) which came with enough wind (Moderate from the South) that wind slabs should be expected behind ridges and in cross-loaded terrain. Coquihalla and Cayoosh Passes have about 50cm of snow on the ground, while treeline areas have around a metre. Alpine areas likely have more snow, but also highly variable depths depending on wind exposure. The main snowpack feature is a rain crust buried early November and now down around 80cm at treeline. A weak layer of facets sitting on top of this crust shows "collapse" fracture character and the ability to propagate. Widespread whumpfing and cracking on this layer has also been reported. It's mostly a concern at upper treeline and alpine elevations on slopes with smooth ground cover (e.g. scree slopes, rock slabs, summer firn, grass, etc.). For more information check out the telemarktips.com forum, the Mountain Conditions Report, and Wayne Flann's Avalanche Blog.
Problems
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 24th, 2012 2:00PM