Avalanche Forecast
Issued: Dec 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
IG,
Avalanche Canada
Fresh snow and wind will create a new reactive storm slab, watch for signs of instability.
A persistent weak layer of surface hoar mid-snowpack, is primed for human triggering. The safest way to manage this problem is through conservative terrain use.
Summary
Confidence
Avalanche Summary
Thursday/Friday, several natural avalanches up to size 2.5 were observed running from the steep terrain of Mt. Macdonald.
Significant human-triggered avalanches have occurred in the past week, all 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.
Snowpack Summary
High freezing levels have left moist snow up to ~2000m, this will form a crust as it cools. 15-25 cms of new snow has fallen over the last few days with wind creating wind slabs at ridgetop
The Dec 1 surface hoar, down 50-100cm, continues to produce 'sudden' results in tests and has been the culprit in several recent close calls from skier-triggered avalanches.
Below 2100m, a rain crust is buried 40-50cm deep.
In shallow areas the base of the snowpack is faceted and unsupportive.
Weather Summary
After Friday's storm we'll see high-pressure building, giving cooler temps and some sun.
Tonight: Trace precip, wind: westerly 20-30km/hr, Freezing level (Fzl) at VB
Saturday: Mix of sun/cloud. Temp: High -10°C, Winds: 15 gusting 40km/hr. Fz lvl 600m
Sunday: Mixed sun/cloud, Temp: High -6°C, Light South wind. Fz lvl 1000m
Monday: Mixed sun/cloud, Temp: High -7°C, light South wind. Fz lvl 1000m
Terrain and Travel Advice
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Problems
Storm Slabs
New snow with wind will create a fresh storm slab. These avalanches have the potential to run far. Allow time for this snow to settle and bond before stepping out into committing terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar down 50-100 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
Valid until: Dec 23rd, 2023 4:00PM
