Avalanche Forecast
Issued: Jan 20th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Deep Persistent Slabs and Persistent Slabs.
jonas hoke,
There is a special avalanche warning in effect for our area. This special warning is in effect immediately, and will apply through to the end of Monday, Jan 24.
Summary
Weather Forecast
The trailing edge of a warm front gives cloudy skies and isolated flurries Friday.
Tonight: Cloudy. Alpine low -9*C. Light, gusting strong, Westerly ridgetop winds
Friday: Cloudy. High -6*C. Mod W winds
Saturday: Sunny periods. Low -5*C, High -1*C. Mod W winds. Alpine temp inversion.
Sunday: Sunny periods. Low -10*C, High -1*C, Freezing level 1500m.
Snowpack Summary
Up to 20cm of new snow and warm temps has created 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
IDA detections indicate that there is an ongoing natural avalanche cycle occurring as of publishing time.
A size 3 deep slab avalanche was triggered by a tree bomb on Abbott Wednesday.
A widespread avalanche cycle occurred on Monday. Size 3-4 avalanches occurred naturally and with artillery control, some with crown lines over 2m deep.
Confidence
Freezing levels are uncertain
Problems
Storm Slabs
Up to 25cm of new snow, combined with warm temps and strong, gusty winds, has built fresh storm slabs. These may lie on a newly formed surface hoar layer.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
- Avoid steep lee and cross-loaded slopes
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
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.
- Avoid thin, rocky or unsupported slopes.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
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.
- Be wary of slopes that did not previously avalanche
- If triggered the persistent slabs may step down to deeper layers resulting in very large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 21st, 2022 4:00PM
