Avalanche Forecast
Issued: Dec 18th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
DH,
Avalanche Canada
A weak layer primed for human triggering continues to produce isolated large avalanches.
The safest way to manage this problem is through conservative terrain use.
Summary
Confidence
No Rating
Avalanche Summary
In our region 5 human triggered avalanches have occurred in the past week failing on the Dec 1st surface hoar layer. In the Connaught drainage a size 2.5 was triggered on Balu Peak, on Ursus Minor a skier narrowly avoided being carried over some cliffs and in the Asulkan valley another avalanche was triggered near the 7 steps. East of the park an experienced group triggered a size 2 avalanche on the same layer with one skier partially buried.
Snowpack Summary
20cm of soft snow covers wind affect or a thin sun crust on steep slopes in the alpine and at tree line or surface hoar in sheltered areas.
Below 2100m a rain crust is buried 40-50cm deep and beneath this, down 50-100cm a weak layer (Dec 1st surface hoar) is persisting and continues to produce 'sudden' results in snowpack tests and has been the failure plane for several recent human triggered avalanches.
In shallow areas the base of the snowpack is facetted and unsupportive.
Weather Summary
No major changes to the current vanilla weather pattern this week. Light to moderate winds with small amounts of new snow continue.
Tues: Cloudy, isolated flurries - trace of new snow, high -2 °C, light SW winds, freezing level 1700m.
Wed: Cloudy, flurries up to 7cm, low -4 °C, moderate SW winds, freezing level 1700m.
Thurs: Cloudy, isolated flurries - trace of new snow, low -5 °C, light SW winds, freezing level 1600m.
Terrain and Travel Advice
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Persistent Slabs
A weak layer of surface hoar down 50-90 cm in the snowpack is at the ideal depth for human triggering and remains reactive. To manage this problem, stick to conservative terrain. Below 2100m this layer may be bridged by a buried rain crust.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Deeper wind-loaded features in the alpine and at treeline may still hold reactive slabs from the recent snow. Allow time for this snow to settle and bond before stepping out into overly committing terrain.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 19th, 2023 4:00PM
