Avalanche Forecast
Issued: Dec 29th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Deep Persistent Slabs and Loose Dry.
Marcus Waring,
Temperatures have moderated slightly on the Icefields Parkway but extra layers & a cautious attitude is still recommended.
Wind slab is our primary concern however deep persistent slabs have been triggered by cornices & surface avalanches recently.
Summary
Weather Forecast
Thursday: A mix of sun and cloud.
Alpine temp: high -20 C. Weak alpine inversion.
Wind: West 10km/h
Friday: A mix of sun and cloud.
Alpine temp: low -23 high -20 C. Weak alpine inversion.
Wind West: 10 km/h
Saturday: Mainly Cloudy with isolated flurries. Trace Precipitation
Alpine high -17
Wind South West 20km/h
Snowpack Summary
Cold temps are faceting the upper snowpack but pockets of wind slab are still present on all aspects at & above tree line. The mid-pack is supportive with the dec 1 crust interface down approx. 40 cm in most locations. Basal faceting continues below the Nov 5 crust potentially amplifying the deep persistent slab problem.
Avalanche Summary
A natural size 2.5 avalanche was observed on Mt. Wilcox during a road patrol today. Estimated date Dec 27th. This avalanche appears to have started as a wind slab, stepping down to deep persistent slab mid path. View min report here
Marmot Basin reported a similar observation with a natural cornice failure triggering deep persistent slab Dec 24.
Confidence
Problems
Wind Slabs
Variable wind direction over the past week has caused reverse loading in many areas.
- Variable winds have created pockets of wind slab on all aspects.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Recent avalanche observations have shown that deep persistent slabs can be initiated by large triggers such as surface avalanches or cornice failures.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Loose Dry
Extra vigilance is warranted in steep terrain, ice climbs, and gully terrain traps where small avalanches can build into larger volumes.
- Be careful of loose dry sluffing in steep, confined or exposed terrain.
- Avoid travelling on ledges and cliffs where sluffing may have severe consequences.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 30th, 2021 4:00PM
