Avalanche Forecast
Issued: Nov 24th, 2012 8:35AM
The alpine rating is Persistent Slabs and Wind Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Due to limited field observations
Weather Forecast
Synopsis: The weather pattern is changing as a ridge of high pressure builds in from the southwest resulting in drier conditions and slightly cooler temperatures for the next few days. Sunday: A mix of sun and cloud. The freezing level is around 800-1000m. Winds are generally light. Monday: A mix of sun and cloud. The freezing level is around 1000m. Tuesday: Should be another dry day, but the next system is forecast to affect the region beginning on Tuesday night or Wednesday morning.
Avalanche Summary
There are no new reports from the region. There was likely enough snow, when combined with strong winds, that natural avalanches released (wind slabs behind ridges?) in some areas. My suspicion is that natural storm snow avalanches have now ended, but the possibility of triggering a lingering pocket remains this weekend.
Snowpack Summary
There are no recent field observations from the region, however weather stations show enough new snow (25-30 cm in the Coquihalla) which came with enough wind (Moderate to strong 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 25th, 2012 2:00PM