Avalanche Forecast
Issued: Dec 15th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
wlewis,
Avalanche Canada
Watch for wind slabs on south facing slopes- northerly winds are redistributing snow into unusual terrain features where it is likely bonding poorly with the crust below.
If triggered, wind slabs have the potential to 'step down' to the weak lower snowpack, creating larger than expected avalanches.
Summary
Confidence
Moderate
Avalanche Summary
No new avalanches have been reported in the past few days.
As northerly winds are expected to continue to redistribute snow, natural and rider triggered wind slabs remain possible.
If you head out into the mountains, please share your photos or observations on the Mountain Information Network. Your information helps us understand local conditions!
Snowpack Summary
In exposed terrain at higher elevations, pockets of wind slab sit in wind loaded features while rocks may be exposed on others.
Large surface hoar has been reported on the surface in sheltered areas, with a crust present on solar aspects. Rising temperatures will likely break down surface snow and create a widespread crust below 2000 m once temperatures cool on Friday afternoon. In sheltered areas below the fresh snow is a large layer of surface hoar. Generally, there's 40 to 70 cm of low-density and weak snow in the upper snowpack.
The mid and lower snowpack consist of crusts and facet layers. These layers are the primary concern for this area. Reports suggest that these layers are a bit stronger than what's found in other regions (e.g. the Duffy or Hurley).
In deeper zones near ridges, the snowpack is around 120 to 170 cm, which is low for early December. Alpine terrain in windy areas is scoured and bare.
Weather Summary
Thursday Night
Clear skies with moderate northerly winds. Freezing level around 500 m.
Friday
Clear skies with an above freezing layer around 1500-2000 m (more significant around the Coquihalla than Allison Pass). Moderate northwest winds. Alpine high of 0 °C.
Saturday
Mostly cloudy with 5 cm of snow possible. Moderate northwest winds. Freezing level below valley bottom. Alpine high of -8 °C.
Sunday
Partly cloudy with around 2 cm of snow expected. Light and variable winds. Freezing level below valley bottom. Alpine high of -20 °C.
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.
- Wind slabs may be poorly bonded to the underlying crust.
- The best and safest riding will be on slopes that have soft snow without any slab properties.
Problems
Wind Slabs
Northerly winds are expected to form fresh, reactive wind slabs in the alpine and treeline. These slabs are expected to form on southerly aspects and may bond poorly to the underlying crust.
With the sugary, faceted, and weak snowpack wind slabs could step down to the middle of the snowpack, resulting in larger than expected avalanches.
Aspects: East, South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 16th, 2022 4:00PM
