Avalanche Forecast
Issued: Dec 10th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
zryan,
Avalanche Canada
The best riding will be found in sheltered terrain. Keep your head up in wind loaded features near ridgeline.
Avoid shallow rocky start zones, deeper weak layers are still a concern.
Summary
Confidence
Weather Forecast
The fast moving pacific system will pass over on Friday night, leaving an unsettled weekend with light to moderate snowfall.
Friday Overnight: As the front tracks south, wind and snow will ease into the evening. Another 5-10 cm of accumulation can be expected with strong to extreme southwest wind easing to moderate at ridgetop by morning. Freezing levels lowering to valley bottom with alpine temperatures around -8 C.
Saturday: A mainly cloudy day with flurries. Moderate to strong ridgetop winds from the southwest, up to 5 cm of new snow throughout the day. Freezing levels at valley bottom with alpine temperatures around -15 C.
Sunday: Partially cloudy with isolated flurries. Light to moderate southwest winds at ridgetop with alpine temperatures around -15 C.
Monday: A pleasant day. A mix of sun and cloud with light to moderate ridgetop winds from the southeast. Light flurries with trace accumulation. Ridgetop winds around -12 C.
Avalanche Summary
On Thursday, our field team was out in the Telkwa mountains, they saw a few natural cornice failures up to size 2.
If you do head out in the backcountry, please share your observations to the Mountain Information Network!
Snowpack Summary
This week's new snow accompanied by strong southwest winds have created wind slabs in the alpine and exposed areas at treeline. These new wind slabs will overlie older wind slabs from earlier in the week, amongst a variety of hard, wind effected surfaces.
Below 1400m, a thin rain crust exists below this week's new snow. There have been reports of faceting around this crust with previous cold temperatures. A spotty surface hoar layer has been reported down ~100cm in the alpine and treeline.
An early season crust can be found near the base of the snowpack. It has shown reactivity in the past week with large loads (explosives and cornice), creating large avalanches. We don't know how widespread this problem may be, but we are definitely keeping an eye on it, and would be avoiding large features and areas with thin to thick snowpack transitions.
Snowpack depth at treeline ranges from 150-200 cm, with higher values in the western part of the region, tapering to the east.
Terrain and Travel
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
Problems
Wind Slabs
Southwest winds have redistribute this week's new snow into wind slabs in the alpine and treeline. These wind slabs may overlie a weak layer of facets or a thin rain crust below 1300m. These weak layers will increase both the reactivity and propagation potential of wind slabs, particularly when a crust is present below.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
An early season crust near the base of the snowpack has shown reactivity in the past week with large explosives' and cornices. We would be avoiding large features, overhead hazard, and areas with thin to thick snowpack transitions.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 11th, 2021 4:00PM
