Avalanche Forecast
Regions: Glacier.
Moderate Southerly winds are reworking the recent storm snow.
Watch for overhead hazards: cornices, touring parties and wind loaded slopes, and limit your exposure.
Confidence
Moderate
Avalanche Summary
One solar triggered loose avalanche size 1.5 on Wednesday in the Portal avalanche path.
Small cycle of natural avalanches over Tuesday night, mostly size 2-2.5, with one isolated size 3.0.
Avalanche control on Tuesday was effective in producing widespread avalanches throughout the park, up to size 3.5, failing in the recent storm snow with large powder components.
Snowpack Summary
50-70 cm of warm, storm snow has created a widespread storm slab. Moderate SW winds during and following the storm loaded lee slopes, in open terrain treeline and alpine.
The mid-snowpack is mainly rounded grains.
The basal Nov 17 deep persistent weak layer is mostly faceted with a decomposing crust in various locations.
Weather Summary
Unsettled weather continues as another low pressure system brings moderate snow Friday with SW winds.
Tonight: Cloudy w/clear periods, Alp low -11*C, light SW winds, FZL valley bottom
Thurs: Cloudy w/sunny periods & isolated flurries, trace snow, Alp high -5*C, Mod SW winds, 1300m FZL
Fri: Flurries, 20 cm, Alp high: -7*C, Mod SW winds gusting to strong, FZL 1300m.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Be especially cautious as you transition into wind affected terrain.
- Caution around slopes that are exposed to cornices overhead.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Avalanche Problems
Storm Slabs
A storm slab is present through out the park. This warm layer of snow is 50-70cm thick. During the storm, moderate S'ly winds loaded lee features and created a thicker, more dense storm slab. Winds on Wednesday continue to load start zones.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 3
Deep Persistent Slabs
This layer has been mainly dormant for the last few weeks but has the potential to 'wake up' with the additional snow load from the storm. Steep, thin, unsupported areas are where this deep layer may be triggered, and the resulting avalanches would be VERY LARGE!
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 2.5 - 4