Avalanche Forecast
Issued: Dec 29th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
bchristie,
Avalanche Canada
Avoid wind exposed slopes at treeline and above, and you'll likely find cold, blower pow. Wind slabs are the main avalanche concern, but consider that ANY problem could get amplified into an emergency on these cold, short days.
Summary
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
Cold arctic air will persist until Sunday, when we are back into a warmer, wetter, westerly weather pattern.Â
WEDNESDAY NIGHT: Overcast. 5-15 cm of low density snow expected. Strong northwest wind, trending to extreme at higher elevations. Temperature @ 1500 m around -12 C.
THURSDAY: Mostly cloudy in the morning, some afternoon sun expected. 0-5 cm of low density snow. Light northwest wind. High temperature @ 1500 m around -10 C.
FRIDAY: Mostly sunny. Light wind from the north, trending to moderate at higher elevations. Low temperature @ 1500 m around -12 C.
SATURDAY: Overcast. Moderate Snowfall. Strong to extreme southwest winds. Temperature @ 1500 m rising to around -7 C.
Avalanche Summary
No new avalanches were reported on Tuesday or Wednesday.
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Some small avalanches were reported on the North Shore mountains over the weekend. These include a few size 1 skier triggered slabs on convex rolls in the Seymour backcountry (see photos in the MIN reports here and here) and some loose dry avalanches in the top 10 cm of low density snow.
Similar avalanche activity can be expected in the upcoming days, although there will be potential for larger slabs at upper elevations as new snow accumulates, especially in lee features, where the wind has increased the loading.
Snowpack Summary
Cold weather has left 30-50 cm of low density snow on the surface. There is potential for northerly winds to begin transporting this snow into wind slabs in unusual locations.Â
This low density snow sits above a mostly settled and bonded snowpack with a few crusts in the top 100 cm.Â
Higher terrain around Squamish may have a lingering weak layer of facets above a crust that formed in early December. This layer is now 150-200 cm deep and has likely transitioned from stubborn to unreactive.
Terrain and Travel
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Recent new snow may be hiding windslabs that were easily visible before the snow fell.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Problems
Wind Slabs
Winds have shifted from south to north with an ample supply of light, cold snow to drift into slabs. Watch for unusual cross-loading or reverse-loading patterns in wind-exposed areas.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 30th, 2021 4:00PM
