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 and Deep Persistent Slabs.
rgoddard,
Avalanche Canada
Watch for wind slab reactivity as this problem continues to build.
The basal snowpack continues to demand thoughtful terrain selection to avoid triggering a very large avalanche.
Keep up the safe travel choices and avoid shallow rocky start zones.
Summary
Confidence
Avalanche Summary
Avalanche control with the use of explosives on Thursday, Friday, and Saturday produced several avalanches up to size 2 (large). These were from storm slabs and wind slabs. These instabilities and the deep persistent slab instability should be assumed to exist in the backcountry.
Snowpack Summary
Around 10 cm of recent snow has been redistributed into small wind slabs in exposed areas. It has been blending into older wind-affected surfaces above 1800 to 2000 m and settling on a crust below this elevation.
A crust/facet layer (2 to 15 cm thick at treeline elevation) is down 50 to 90 cm. 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
Saturday Night
Cloudy, 2 to 5 cm accumulation, 10 to 20 km/h southwest wind gusting to 50, temperature dipping to -8 C.
Sunday
Cloudy, up to 8 cm accumulation with a chance of snow showers, 10 to 15 km/h west winds, temperatures reaching -3 C.
Monday
Cloudy, up to 4 cm accumulation, 15 km/h northwest wind gusting to 35, temperatures -8 to -4 C.
Tuesday
Cloudy with sunny breaks, trace accumulation, 15 km/h southwest wind gusting to 40, temperatures -10 to -5 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.
Problems
Wind Slabs
Elevated winds have likely formed wind slabs on leeward slopes along ridge crests at higher elevations. Expect any you encounter to remain reactive to human triggering on Sunday.
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. Where supportive to riders, a melt-freeze crust may be providing a bridging effect, making it more difficult to trigger deeper layers. Any avalanche triggered this deep will likely be large and destructive.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 22nd, 2023 4:00PM
