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.
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.
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.
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.
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.
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.
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.
