Avalanche Forecast
Regions: Glacier.
The persistent weak layer (PWL) in the upper snowpack is our main concern.
Gathered info shows a gradual strengthening in the upper snowpack, but uncertainty of the buried PWLs reactivity has snow professionals traveling with a cautious/conservative mindset.
Rugged and variable snow conditions are present below Treeline.
Confidence
Moderate
Avalanche Summary
Numerous wet loose and slab avalanches occurred the past week with daytime warming and solar input. These avalanches were up to size 3.0 and often gouged to ground at lower elevations where the snowpack had become isothermal.
Though the natural avalanche cycle has slowed, human triggering remains possible.
Neighbouring operations have been seeing very large skier remote triggered avalanches on the facet interfaces down 30-80cm.
Snowpack Summary
The top 15cm in the upper snowpack has undergone a melt-freeze cycle on all aspects below treeline, and on solar aspects into the alpine. The 40cm of storm snow that fell last week sits on a very faceted (sugary) upper snowpack.
A persistent weak layer (PWL) of surface hoar, facets and/or suncrust (Jan 30th) is 50-80cm down. Feb 16 is another PWL (facets/crust/surface hoar) down 30-40cms. Both of these layers are reactive to human triggering.
Weather Summary
A minor system slides through the area, bringing flurries and moderate gusty winds overnight and into Wed.
Tonight Cloudy, flurries. 5cm. Alpine low -7°C. Ridge winds 15-25km/h. Freezing level (FZL) 1100m
Wed Mainly cloudy. Trace snow. Alp high -6°C. Light W wind. FZL 1500m
Thurs Mix of sun and cloud. Alp high -4°C. Light NW wind. FZL 1600m
Fri Cloudy with sunny periods. Alp high -5°C. Light W wind. FZL 1400m
Terrain and Travel Advice
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and slopes above cliffs.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Avalanche Problems
Persistent Slabs
Last week's storm buried a persistent weak layer (PWL) that consists of suncrust, facets and/or surface hoar in some locations. Warm temps promoted the settling of a cohesive slab on top of this layer. Expect this slab to become more reactive during times of intense solar input.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 2.5