Avalanche Forecast
Regions: Dogtooth, East Purcell, Esplanade, Purcells.
Wind slabs are showing reactivity to rider-triggered avalanches.
Weaker layers buried further down may be triggered where the snowpack is shallower.
Terrain choice will be key in seeking out the best and safest riding.
Confidence
Low
Avalanche Summary
Skier-triggered avalanche from a wind slab was reported south of the Golden area on Wednesday. Signs of whumpfs and cracking were also reported.
Rider-triggered avalanches are to be suspected throughout our region in wind-affected terrain.
On Sunday there were reports of avalanches failing on the Mid-November surface hoar layer. Triggering this layer is still possible.
Thank you to those reporting your observations. If you head out into the backcountry please continue to support your community by sharing in the MIN.
Snowpack Summary
Around 10 cm of new low-density snow has fallen in recent days. Consistent and strong westerly winds likely transported what snow was available. Fresh wind slabs in the alpine and treeline. In exposed terrain, some slopes have been scoured back to rock.
A buried layer of surface hoar sits 15 - 30 cm deep and remains a layer of concern, especially once a stiffer slab sits above it.
The prolonged cold temperatures have weakened the generally thin snowpack, promoting faceting as a whole.
The overall height of snow is highly variable throughout the region with around 40-140 cm in the alpine.
Weather Summary
Thursday Night
Mostly cloudy, trace accumulation, wind south 20 km/h, temperature -6 C at 1500 m.
Friday
A mix of sun and cloud, trace accumulation, winds south 15 to 25 km/h, temperature -8 C at 1500 m.
Saturday
Cloudy with sunny periods, 2 cm accumulation, winds southeast 20 km/h, temperature -10 C at 1500 m.
Sunday
A mix of sun and cloud, trace accumulation, winds northeast 10 km/h, temperature -9 C at 1500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- In times of uncertainty conservative terrain choices are our best defense.
Avalanche Problems
Wind Slabs
Consistent winds and low-density snow have developed a wind slab on lee aspects and on cross-loaded terrain.
These slabs likely overlay a weak, sugary lower snowpack. If triggered, small avalanches may trigger a bigger avalanche by 'stepping down' to these weak crystals.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5
Persistent Slabs
Buried layers of surface hoar and facets were last reported active on Sunday. Suspect triggering to be its highest in areas where the snowpack is shallower.
This layer will be most evident in sheltered areas at treeline, where surface hoar may be preserved, and in wind-loaded areas at upper elevations where a cohesive slab above has formed.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2.5