Avalanche Forecast

Issued: Dec 27th, 2023 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Carefully assess conditions as you gain elevation, triggering slab avalanches is likely on steep wind-loaded slopes.

Summary

Confidence

Moderate

Avalanche Summary

On Tuesday several small (size 1) wind slab avalanches were triggered by riders north of Pemberton and some larger natural and human-triggered slab avalanches were observed just outside of the region (south side of the Pemberton Valley).

Wind slabs remain a concern with ongoing loading from new snow and wind.

Snowpack Summary

10 to 25 cm of new snow is coming with strong south wind on Thursday. This adds to 20 to 40 cm of heavily wind-affected snow from the past week. This recent snow sits on crusts and, in some sheltered areas, surface hoar. This layer has bonded poorly in neighbouring regions to the west and south, and in parts of this region could result in large wind slab avalanches.

Overall, the snow depth remains shallow, with average treeline snowpack depths between 70 and 100 cm.

Weather Summary

Wednesday Night

Cloudy with 5 to 15 cm of snow above 1200 m (rain below), alpine wind south 40 to 70 km/h, treeline temperature -2 °C.

Thursday

Cloudy with 5 to 10 cm of snow above 1400 m (primarily in the morning then easing in the afternoon), alpine wind southwest 20 to 40 km/h, treeline temperature -2 °C, freezing level climbing to 1600 m in the afternoon.

Friday

Mix of sun and cloud with no precipitation, alpine wind south 20 to 40 km/h, treeline temperature around +2 °C with freezing level climbing to 2400 m.

Saturday

Mostly cloudy with up to 1 cm of snow, alpine wind south 20 km/h, treeline temperature around 0 °C with freezing level dropping to 1800 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Wind slabs may be poorly bonded to the underlying crust.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs will be most reactive where they sit over a layer of surface hoar or a hard crust.

Aspects: North, North East, East, West, North West.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Valid until: Dec 28th, 2023 4:00PM

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