Avalanche Forecast
Regions: Pine Pass.
There is uncertainty with the reactivity of deeply buried weak layers with recent warming and new snow. It is best to manage this uncertainty by sticking to lower angle terrain away from any overhead hazard.
Read more in our latest forecaster blog.
Confidence
Moderate
Avalanche Summary
Recent reports indicate explosives controlled wind slab avalanches to size 2.5 running on east and southeast aspects in the alpine.
Reactive wind slabs will continue to form, but concern for step-down and large natural and human-triggered deep persistent slab avalanches is at the forefront of our minds. Check out this video on incremental loading to learn more.
Please continue to send in your observations through the MIN.
Snowpack Summary
Recent new snow accompanied by strong northwest winds continues to build wind slabs in lee terrain.
Snowpack depths are shallower than normal, and several buried weak layers have been a concern over the past few weeks. Surface hoar or crust layers in the mid-snowpack may exist in this region, but field observations suggest these mid-snowpack weaknesses are less prominent here than in areas further south.
The most concerning layer in this area is at the base of the snowpack. Large, weak facets buried in November are widespread. This layer is most likely to be problematic in steep, rocky alpine terrain, where shallower wind slab avalanches can scrub down to these basal facets.
Weather Summary
Wednesday Night
Cloudy with clear breaks and isolated flurries. Ridge wind northwest 50-80 km/h. Alpine temperature -3 C. Freezing level 1400 m.
Thursday
Cloudy with sunny breaks. Ridge wind northwest 40-80 km/h. Alpine temperature -4 C. Freezing level 1500 m.
Friday
Mainly cloudy with flurries. Ridge wind northwest 15-40 km/h. Alpine temperature -8 C. Freezing level valley bottom.
Saturday
Mainly sunny. Ridge wind northeast 45 km/h. Alpine temperature -15 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- 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.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Uncertainty is best managed through conservative terrain choices at this time.
Avalanche Problems
Wind Slabs
Strong northwesterly winds will continue to transport surface snow and form fresh, reactive wind slabs in the alpine and treeline.
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1.5 - 2.5
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer has most recently been problematic in upper treeline/lower alpine elevations.
Riders are most likely to trigger an avalanche on this layer in steep, shallow previously undisturbed terrain or by first triggering a layer further up in the snowpack.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3.5