Avalanche Forecast
Issued: Dec 13th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
ahanna,
Avalanche Canada
A spooky buried weak layer is here to stay for the foreseeable future. Conservative decision making is key. Check out our latest blog for advice on how to manage this problem.
Summary
Confidence
Moderate
Avalanche Summary
Over the past week, we've had reports of persistent slab avalanches on a buried weak layer. On the weekend, two skier-triggered size 2 avalanches were reported ~40 cm deep at treeline near Golden. Otherwise, persistent slab avalanches throughout the region have been mostly explosive controlled, size 1-2.
In the neighboring central Columbia and west Kootenay regions, where the weak layer is buried deeper, reports of avalanche activity on this layer have been piling up daily. Unfortunately, this is more likely than not a sign of what is to come for the Purcells.
Snowpack Summary
5-10 cm of recent snow sits on a variety of surfaces ranging from hard wind slabs to soft, unconsolidated facets.
A concerning weak layer composed of surface hoar, facets and/or a crust that formed in mid November is now buried 15-40 cm deep. Avalanche activity has been observed on this layer and is expected to continue as the overlying snow takes on more slab character due to settlement, wind and additional snow load.
Alpine snowpack distribution is variable, with depths ranging from 40 to 140 cm.
Weather Summary
Tuesday night
Scattered flurries bringing a trace of snow. Calm to light northerly wind. Alpine low of -12 C.
Wednesday
A mix of sun and cloud. Light northerly wind. Alpine high of -7 C.
Thursday
Sunny. Light northerly wind. Alpine high of -9 C.
Friday
A mix of sun and cloud. Winds switching westerly and building to strong at ridgetop. Alpine high of -11 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Be especially cautious as you transition into wind affected terrain.
- Avoid rock outcroppings, convexities, and anywhere the snowpack is thin and/or variable.
Problems
Persistent Slabs
A buried weak layer composed of surface hoar and facets is becoming increasingly problematic as overlying snow accumulates and gains slab property. This layer is most likely found in sheltered areas at treeline and below.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Wind slabs may remain reactive to human triggers, especially where they overlie a weak, sugary lower snowpack.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 14th, 2022 4:00PM
