Avalanche Forecast
Regions: Glacier.
The potential remains to trigger the deep persistent slab from early December. Stick to conservative terrain while the snowpack adjusts to the new snow load.
Weather Forecast
A frontal system brings snow and warming temperatures Thursday.
Tonight: Scattered flurries (5cm). Alpine low -8*C. Light SW ridgetop winds
Thursday: Snow (15cm). Alpine high -4*C. Freezing level 1400m. Strong gusty SW winds
Friday: Cloudy with isolated flurries. Low -10*C, High -6*C. Light/mod W winds
Saturday: Sunny periods. Low -6*C, High -1*C.
Snowpack Summary
Up to 20cm of new snow and warm temps will build fresh storm slabs over 2-4mm surface hoar.
There are 2 PWLs in the mid-pack: surface hoar is 50-80cm down at and below treeline,a layer of facets from Xmas is down ~100cm.
The Dec 1 crust/facet combo is down ~2-2.5m - this layer came alive last storm, and will be a lingering concern for a long time.
Avalanche Summary
A size 3 deep slab avalanche was triggered by a tree bomb off the shoulder of Abbott on Wednesday.
Neighbors triggered the Dec. 1st crust with heli-bombing on Tuesday.
A large avalanche cycle occurred in the Pass Monday. Size 3-4 avalanches were observed on the W side of the Pass (Fidelity, Camp West, McGill, Smart and Gunners), with crowns over 2m.
Confidence
Freezing levels are uncertain
Avalanche Problems
Storm Slabs
20cm of snow is forecast, along with warm temps and strong, gusty winds. Expect fresh storm slabs to build through out the day. These may lie on a newly formed surface hoar layer.
- Minimize overhead exposure during periods of heavy loading from new snow, wind.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2.5
Deep Persistent Slabs
The Dec 1 crust/facet combo came to life on Monday, resulting in numerous very large avalanches.
This is now a low probability/high consequence avalanche problem. It will be stubborn to trigger, but if it goes it will be huge.
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
- Avoid thin, rocky or unsupported slopes.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely
Expected Size: 2 - 4
Persistent Slabs
Multiple persistent weak layers in skiable terrain awoke with Monday's storm. The Jan 11 surface hoar and New Years facets were the suspected failure plane for several avalanches that stepped down to the Dec. 1st crust/facet layer.
- If triggered the persistent slabs may step down to deeper layers resulting in very large avalanches.
- Be wary of slopes that did not previously avalanche
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 3