Avalanche Forecast
Issued: Jan 23rd, 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.
CG,
Avalanche Canada
Strong SW winds have been blowing through Rogers Pass, rapidly building reactive wind slabs in lee and cross-loaded areas.
These new slabs need your respect, as they have the potential to overload the persistent slabs in the upper snowpack.
Summary
Confidence
Avalanche Summary
A field team on Connaught/Lookout triggered a sz 1 wind slab, which stepped down to the Jan 3 surface hoar. They also observed several sz 1 loose/dry avalanches on the N Face of MacDonald, running in extreme terrain.
Cheops North 4 ran sz 2 Monday morning, while Frequent Flyer ran sz 2 on Sat into the creek.
Lens Gully had a sz 2.5 run end path Mon morning.
Snowpack Summary
Reactive wind slabs are popping out at Tree-line and Alpine elevations, stepping down into the Jan 3 persistent weak layer.
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
Unsettled weather follows Monday's cold front, bringing clouds and isolated flurries the next few days.
Tonight: mainly cloudy, flurries, trace snow, 400m FZL, moderate gusty SW winds
Tues: mainly cloudy, trace snow, Alp high -8*C, light/gusting mod W ridge winds, 900m FZL
Wed: mainly cloudy, isolated flurries, trace snow, Alp high -4*C, 1400m FZL, light W 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
Strong S/SW winds are transporting the low density surface snow and forming wind slab at Tree-line and Alpine elevations.
Watch for these along ridge lines, lee areas and cross loaded features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
This layer is buried ~40cm and will be most reactive at ridgeline or in open lee features where new wind slab has formed. If triggered, this slab has the potential to step down to the deep persistent layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
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 cautious in steep, rocky areas with thin snow coverage, where the majority of the snowpack is weak and faceted.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 24th, 2023 4:00PM
