Avalanche Forecast
Issued: Dec 12th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
lbaker,
Avalanche Canada
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Carefully assess convex slopes and open rolls where a weak layer of surface hoar may be preserved.
Summary
Confidence
Moderate
Avalanche Summary
No new avalanches have been reported in the region on Tuesday.
This weekend size 1 to 2, natural storm slab avalanches were observed failing on the buried surface hoar layer down 40 - 50 cm at upper treeline.
If you're heading out in the backcountry, please consider sharing any observations on the Mountain Information Network
Snowpack Summary
20 to 30 cm of recent snow has been heavily wind affected in the alpine. Recent snow overlies a supportive crust at lower elevation which tapers out at 1950 m. 40-50 cm down a weak layer of surface hoar is preserved in sheltered areas at treeline. Below this is a series of crusts and basal facets.
Overall, the snow depth remains relatively shallow, creating challenging travel conditions and numerous hazards present at or just below the snow surface across all elevations.
Weather Summary
Tuesday Night
Mainly clear skies with no precipitation, southwest alpine winds 30 to 50 km/h, treeline temperature 0 °C, an above freezing layer remains between 1700 and 2500 m overnight.
Wednesday
Mix of sun and cloud with isolated flurries, 2-5 mm accumulation, southwest alpine winds 70 to 100 km/h, treeline temperature 0 °C, freezing levels 1600 m.
Flurries continue overnight bringing another 5 to 10 mm of accumulation.
Thursday
Mainly cloudy with scattered flurries, 2 to 5 mm accumulation, west alpine winds 10 to 30 km/h, treeline temperature -4 °C, freezing levels 800 m.
Friday
Mix of sun and cloud with isolated flurries, trace accumulation, southwest alpine winds 50 to 70 km/h, treeline temperature -2 °C, freezing levels 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Wind slabs are most reactive during their formation.
- Surface hoar distribution is highly variable. Avoid generalizing your observations.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.
Problems
Wind Slabs
Watch for pockets of fresh wind slab in alpine lees as strong southwest winds redistribute available snow.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of large surface hoar is found down 40 to 50 cm. Human-triggering this layer above 1900 m is still possible. Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 13th, 2023 4:00PM
