Avalanche Forecast

Issued: Nov 28th, 2022 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs.

Avalanche Canada shorton, Avalanche Canada

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Recent snow overlies various layers that could produce slab avalanches on specific terrain features.

Summary

Confidence

Moderate

Avalanche Summary

Over the weekend 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.

At this point, avalanches on this layer are most likely to be small and on isolated terrain features, but it will likely become a more serious problem when new snow arrives on 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

Monday Night

Cloudy with light flurries and trace amounts of snow in the south (South Okanagan and West Kootenays) and mostly clear skies in the north (Shuswap), light wind from the northeast, treeline temperatures cool to -15 °C.

Tuesday

Increasing cloud with isolated afternoon flurries, trace amounts of snow, light wind from the south, treeline temperatures steady around -15 °C.

Wednesday

Cloudy with snowfall, accumulations of 15 to 30 cm, 40 km/h wind from the south, treeline temperatures warm to -10 °C.

Thursday

Partly cloudy, isolated flurries with up to 5 cm of snow, light wind from the north, treeline temperatures around -12 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Exercise caution on steep, unsupported slopes.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

Problems

Storm Slabs

An icon showing 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

Possible

Expected Size

1 - 1.5

Valid until: Nov 29th, 2022 4:00PM

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