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 and Deep Persistent Slabs.
rgoddard,
Avalanche Canada
Be mindful of wind slabs and overhead hazards as you transition into exposed terrain.
The complex snowpack continues to demand thoughtful terrain selection to avoid triggering a very large avalanche.
Summary
Confidence
Moderate
Avalanche Summary
Sunday saw a cornice fail naturally but it did not trigger buried weak layers in this instance. Be aware of what is above you as you travel through the terrain.
Although they have not produced avalanches in the last few days, instabilities from the deep persistent slab still exist and should be assumed to be lurking in the backcountry.
Snowpack Summary
Soft thin wind slabs have developed in exposed areas. It has been blending into older wind-affected surfaces above 1800 to 2000 m. Below this elevation, recent snow has settled on a melt-freeze crust that developed earlier this month.
A crust/facet layer, 2 to 15 cm thick at treeline is 50 to 90 cm below the surface. Where it's thickest, it caps the settled and consolidated mid-snowpack.
Another crust/facet layer is down 70 to 150 cm. Below this crust, the basal snowpack is weak and faceted. The total snowpack depth ranges between 120 and 250 cm.
Weather Summary
Monday Night
Cloudy, trace accumulation, wind southwest 27 km/h, treeline temperatures -10 C.
Tuesday
Cloudy with sunny breaks, trace accumulation, wind west 22 km/h increasing later in the day, treeline temperatures -8 C with freezing level rising to 1000 m.
Wednesday
Cloudy with increasing sunny periods later in the day, potential trace accumulation, wind west 15 km/h, treeline temperatures -5 C.
Thursday
Mostly cloudy, trace accumulation, wind west 17 km/h, treeline temperature -4 to 0 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Avoid exposure to slopes that have cornices overhead.
Problems
Wind Slabs
Wind slabs exist in the alpine and can be found on leeward slopes and along ridge crests at higher elevations. Expect them to remain reactive to human triggering.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Faceted grains make up the basal snowpack and are gaining strength very slowly. This layer has been relatively quiet recently but can still be triggered with a heavier load, like a cornice fall for example, and in areas with a thinner snowpack. Any avalanche triggered this deep will likely be large and destructive.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 24th, 2023 4:00PM
