Avalanche Forecast
Issued: Nov 29th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
jpercival,
Avalanche Canada
Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding, and conservative decision-making are essential. Recent snow overlies various layers that could produce slab avalanches on steep terrain features.
Summary
Confidence
Low
Avalanche Summary
Over the past week, a few small (size 1) avalanches were reported south of Nelson. There were also reports of whumpfing and cracking suggesting the recent snow is poorly bonded to the mid-November weak layer.
Avalanches on this layer are most likely to be small and found on isolated terrain features, but it will likely become a more serious problem when new snow arrives Tuesday night and Wednesday.
Snowpack Summary
Early season conditions exist with low snow amounts and crusts found at lower elevations and a deeper and drier snowpack approaching 1 m at treeline and alpine elevations.
Around 30 cm of snow overlies a weak layer that formed mid-November that consists of sugary faceted grains, weak surface hoar crystals in sheltered terrain features, and a hard crust on steep sun-exposed slopes.
The remainder of the snowpack is faceted as shown in this MIN, but is likely still intermixed with rocks, brush, and trees.
Weather Summary
Wednesday Night
Cloudy with flurries and 1 to 3 cm, 40 km/h wind from the southwest, treeline temperatures -12 °C.
Thursday
Cloudy with snowfall, accumulations of 10 to 15 cm, 70 km/h wind from the southwest, treeline temperatures warm to -9 °C.
ThursdayPartly cloudy, isolated flurries with trace amounts of snow, light wind from the north, treeline temperatures around -15 °C.
FridayClear sky no forecast precipitation, 10 km/h variable wind, treeline temperature -10 to -15 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Remote triggering is a concern, watch out for adjacent and overhead slopes.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Problems
Storm Slabs
Around 30 cm of recent snow overlies various layers formed mid-November, including surface hoar, faceted grains, and a hard crust. The recent snow may not bond well to these layers.
Wind may have redistributed the storm snow at high elevations, forming isolated wind slabs in lee terrain features.
Avalanche hazard is unlikely anywhere snowpack depths have yet to overcome ground roughness like brush and rocks.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 30th, 2022 4:00PM
