Avalanche Forecast
Issued: Dec 13th, 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.
lbaker,
Avalanche Canada
Dangerous avalanche conditions exist where new snow buries a layer of weak surface hoar. Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Summary
Confidence
Moderate
Avalanche Summary
No recent avalanches have been reported in the region.
This weekend several size 2, natural storm slab avalanches were observed, failing on the buried surface hoar layer down 60 to 70 cm at upper treeline. Avalanche activity has not been observed on these layers in the last few days however, they continue to be reactive in snowpack tests.
If you're heading out in the backcountry, please consider sharing any observations on the Mountain Information Network.
Snowpack Summary
+15 cm of storm snow overlies variable surfaces including wind affected surfaces in the alpine, large surface hoar in sheltered areas and a crust at lower elevations.
At treeline and above there are two layers of concern in the mid-pack. A crust is found down 30 to 50 cm; in sheltered areas, a weak layer of surface hoar is found above the crust. A second crust with a weak layer of surface hoar above it is found down 60 to 70 cm.
In general, the snowpack is still shallow for this time of year with snowpack depths at treeline ranging from 80 to 120 cm. Early season hazards are still a concern.
Weather Summary
Wednesday Night
Mix of sun and cloud with flurries, 10-15 mm accumulation, southwest alpine winds 20 to 30 km/h, treeline temperature -3 °C, freezing levels 1000 m.
Thursday
Mainly cloudy with scattered flurries, 4 to 12 mm accumulation, southwest switching to northwest alpine winds 20 to 40 km/h, treeline temperature -2 °C, freezing levels 1200 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.
Saturday
Mix of sun and cloud with isolated flurries, trace accumulation, southwest alpine winds 60 to 80 km/h, treeline temperature -2 °C, freezing levels 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- Storm slab size and sensitivity to triggering will likely increase through the day.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
Problems
Storm Slabs
+15 cm of storm snow and strong southwest winds are creating reactive storm slabs at higher elevations. Investigate the bond of new snow to surfaces below while traveling through terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of large surface hoar is found down 60 to 70 cm. Human-triggering this layer above 1900 m is still possible. Investigate open slopes and convex rolls where buried surface hoar may be preserved before stepping out.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 14th, 2023 4:00PM
