Avalanche Forecast
Regions: Tutshi, Wheaton, White Pass East, White Pass West, Yukon.
A deeply buried weak layer continues to produce large avalanches, and a conservative mindset is recommended. Watch for fresh slabs where wind moves loose snow.
Confidence
Low
Avalanche Summary
On Tuesday and Wednesday, two natural cornice-triggered size 3 slab avalanches occurred in steep terrain. At least one of these failed on the early-Dec weak layer. An older natural size 3 slab avalanche was also observed above Bryant Lake (MIN report).
On Tuesday, the field team observed two older size 2 wind slabs from the highway and an old snowmobile triggered size 2 in the Fraser Chutes.
Last week, a remotely triggered size 3 persistent slab occurred (MIN report).
Snowpack Summary
30-50 cm of settling storm snow from the last week can be found in sheltered terrain. Exposed terrain has been heavily wind-affected.
A weak layer of facets and a crust from early December is buried 80 to 140 cm deep. This layer exists on all aspects up to around 1700 m and recently produced large avalanches.
Check out this recent ACMG Mountain Conditions Report for more on the persistent weak layer problem.
Weather Summary
Thursday night
Mostly cloudy with isolated flurries, trace accumulation. 30 to 50 km/h west ridgetop wind. Treeline temperature -9 °C.
Friday
A mix of sun and cloud. 40 to 60 km/h west ridgetop wind. Treeline temperature -4 °C.
Saturday
Cloudy with sunny breaks. 40 to 60 km/h west ridgetop wind. Treeline temperature -3 °C.
Sunday
Cloudy with isolated flurries, trace to 5 cm. 50 to 70 km/h southwest ridgetop wind. Treeline temperature -3 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for large avalanches due to buried weak layers.
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.
Avalanche Problems
Wind Slabs
Ongoing steady wind will continue to build wind slabs in exposed terrain. Older wind slabs may remain reactive to human triggering.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Persistent Slabs
A weak layer of facets and a crust down 80 to 140 cm produced several large avalanches in the past week. It's likely most sensitive in shallow, or thin to thick areas. Remotely triggered avalanches and wide propagations remain possible.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3.5