Avalanche Forecast
Issued: Jan 21st, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
MH,
Avalanche Canada
Fresh pockets of wind slab likely exist in the Alpine. New snow and wind will continue to add to the load over the early January surface hoar. Be cautious in wind-loaded terrain where this layer may be getting buried deep enough to produce large avalanches.
Summary
Confidence
Moderate
Avalanche Summary
Frequent Flyer ran size 2.0 over the Connaught Valley skin track into the creek around noon on Saturday. The debris pile was ~1m deep and 10m wide.
A steady stream of size 1-1.5 skier-triggered avalanches have been reported over the last few days, likely failing on the Jan 3 surface hoar which is buried ~35cm.
Snowpack Summary
Fresh pockets of wind slab in the alpine exist in some locations. Early Jan surface hoar layers are present in the upper 40cm.
The mid-pack facets are slowly rounding and gaining strength, while the basal facets and Nov 17 facet/SH/crust weakness are still reactive when isolated in snowpack tests.
Weather Summary
Sunday will see mainly cloudy skies with 15-30km/hr Westerly winds. The alpine high will be -12 with the freezing level remaining at valley bottom as cooler temps settle in.
5cm for Monday into Tuesday with strong winds.
Terrain and Travel Advice
- Be especially cautious as you transition into wind affected terrain.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Wind Slabs
Gradual snow fall amounts of low density snow and increasing winds have likely formed fresh wind slabs in the alpine. Watch for these along ridge lines, lee areas and cross loaded features.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
Expect renewed reactivity as wind and a bit of new snow add to the load on the Jan 3 surface hoar (5-10mm). This layer is buried ~40cm and will be most reactive at ridgeline or in open lee features, where wind has stiffened the surface. If triggered, this slab has the potential to step down to the deep persistent layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
The Nov 17 layer, which consists of a faceted crust and decomposing surface hoar, highlights a weak basal snowpack. Be particularly cautious in steep, rocky areas with thin snow coverage, where the majority of the snowpack is weak and faceted.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 22nd, 2023 4:00PM
