Avalanche Forecast
Issued: Dec 12th, 2020 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.
shorton,
Avalanche Canada
Heightened avalanche conditions exist on wind loaded slopes and steep rocky terrain.
Summary
Confidence
Moderate - Recent weather patterns have resulted in a high degree of snowpack variability within the region.
Weather Forecast
SATURDAY NIGHT: Partly cloudy, light southwest wind, low temperatures around -12 C.
SUNDAY: Cloudy with some light flurries in the afternoon, light southwest wind, high temperatures around -8 C.
MONDAY: Mix of sun and cloud, light west wind, high temperatures around -6 C.
TUESDAY: Light flurries with a trace of new snow, moderate southwest wind, high temperatures around -6 C.
Avalanche Summary
Explosive control work produced a few small (size 1) storm slab avalanches on Thursday and Friday. Natural, skier and explosive triggered storm slab avalanches up to size 2 were reported throughout the region during the storm Tuesday and Wednesday.
Snowpack Summary
10-30 cm of recent snow overlies a rain crust found up to 2400 m in the south of the region and 1800 m in the north. In the north, the recent snow may sit over a weak layer of surface hoar or facets at elevations around treeline where this crust is not found or where it is a very thin lens that formed above these weak layers. The recent snow does not appear to be bonding well to these old surfaces.
The lower snowpack is characterized by a couple of crusts, the most notable is from a rain event in early November that is 50 to 100 cm deep. This crust is sitting near the base of the snowpack, surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers or in a step-down from a smaller avalanche in shallow, rocky areas.
Terrain and Travel
- Investigate the bond of the recent snow
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Wind Slabs
10-30 cm of snow that fell earlier this week may be blown into unstable slabs. In certain areas this snow may be poorly bonded to underlying layers of surface hoar and/or crusts. The problem is more likely found in northern parts of the region that received more snow.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A facet/crust layer from early November sits near the base of the snowpack. This layer has shown signs of recent reactivity with explosive control in shallow rocky locations producing large avalanches. It is most likely to be triggered by humans in shallow, rocky areas or in a step-down from a smaller avalanche.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 13th, 2020 4:00PM
