Avalanche Forecast

Issued: Mar 9th, 2022 4:00PM

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

Avalanche Canada mconlan, Avalanche Canada

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Assess for instability before committing to consequential terrain.

Summary

Confidence

High - Confidence is due to a stable weather pattern with little change expected.

Weather Forecast

WEDNESDAY NIGHT: Clear skies with no precipitation, 20 km/h northwest wind, alpine temperature -10 C.

THURSDAY: Mix of sun and cloud with no precipitation, 20 km/h southwest wind, alpine temperature -7 C.

FRIDAY: Cloudy with snowfall, accumulation 5 cm, 30 to 50 km/h southwest wind, alpine temperature -6 C.

SATURDAY: Cloudy with snowfall, accumulation 5 cm, 40 km/h southwest wind, alpine temperature -5 C.

Avalanche Summary

A rider triggered a persistent slab avalanche along the Duffey on Wednesday, occurring at 2000 m on a northeast aspect. Another suspected persistent slab avalanche was triggered by a rider on Tuesday in the north of the region. Both slabs were around 30 to 40 cm thick, resulting in small avalanches (size 1 to 1.5). 

It remains possible that humans could trigger this layer, where it exists.

Snowpack Summary

5 to 10 cm of recent snow sits on a hard melt-freeze crust on all aspects below around 1600 m and on sun-exposed slopes into the alpine. Settled dry snow remains on shaded slopes above around 1600 m. Reports suggest that recent northerly wind did not form new wind slabs, though extra caution is advised in steep terrain where isolated pockets may have formed.

Around 30 to 60 cm deep, sugary faceted grains may be found around a melt-freeze crust that formed February in the north of the region (e.g., Duffey, Hurley). The layer is most prevalent on northeast to northwest aspects at treeline and alpine elevations. This layer should be treated as suspect anywhere it exists. Check out this forecaster blog for more info. Various crusts may be found in the south of the region (e.g., Coquihalla, Manning) but reports suggest they are bonding to the snowpack and are not an avalanche concern.

There are no deeper concerns at this time.

Terrain and Travel

  • Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

Problems

Persistent Slabs

An icon showing Persistent Slabs

Portions of the north of the region (e.g. Duffey, Hurley) have a a weak layer of faceted grains above a hard melt-freeze crust that is found 30 to 60 cm below the snow surface. A few avalanches over the past week have released on it, with more activity observed in the neighbouring Sea to Sky region. It is most likely to be problematic on northwest to northeast aspects at treeline and alpine elevations.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Valid until: Mar 10th, 2022 4:00PM

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