Avalanche Forecast
Regions: Dogtooth, East Purcell, Purcells.
Although avalanche activity has tapered off, buried weak layers are still reactive to rider triggering.
Cold temperatures and shorter days should play a role in your trip plan.
Confidence
Moderate
Avalanche Summary
Avalanche control continues to trigger the mid-November weak layer, producing up to size 2 avalanches. Natural and rider-triggered activity on this layer has died down over the past week but in the neighboring central Columbia region, where it is buried deeper, this layer continues to produce rider-triggered avalanches up to size 2.5. Cold temperatures and little snowfall are not likely going to help heal this layer.
Snowpack Summary
Up to 15 cm overlies variable surfaces ranging from hard old wind slabs in exposed features at upper elevations to soft, unconsolidated facets in sheltered areas.
A concerning weak layer composed of surface hoar, facets, and/or a crust that formed in mid-November is now buried 40 to 80 cm deep. Avalanche activity on this layer has tapered off but it is likely still possible to trigger this layer in isolated terrain features at treeline.
Alpine snowpack distribution is variable, with depths ranging from 70 to 140 cm.
Weather Summary
Sunday Night
Cloudy, up to 2 accumulation, 10 to 15 km/h northeast wind, temperature -25 C at 1500 m.
Monday
A mix of sun and cloud, trace accumulation, 10 km/h northeast winds, temperature -25 C at 1500 m.
Tuesday
Sunny with cloudy periods, no accumulation, 15 km/h southeast wind, temperature -20 C at 1500 m.
Wednesday
Mostly sunny, no accumulation, 10 km/h northwest winds, alpine temperature of -25 to - 30 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid open slopes and convex rolls at and below treeline where weak layers may be preserved.
- Keep in mind that human triggering potential persists as natural avalanching tapers off.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
Avalanche Problems
Persistent Slabs
A layer of surface hoar, facets and a crust from mid november is buried around 40cm deep but can be found down as much as 80 cm. This layer is most likely to be rider triggerable on slopes at treeline where the snow above feels stiff and consolidated. Avalanche activity on this layer has been decreasing over the week but it's not likely to go away with the continuing cold temperatures.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2
Wind Slabs
Wind slab could be found on all aspects in the alpine. These slabs could be more reactive where they overlie facets. If triggered their likely hood of creating large avalanches is high if they "step down" to buried weak layers.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 1 - 1.5