Avalanche Forecast
Issued: Dec 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
wlewis,
Avalanche Canada
Look for sheltered terrain to avoid wind slabs.
Storm snow likely needs time to bond with the old snow surface.
Summary
Confidence
Avalanche Summary
Initial reports suggest widespread natural avalanche activity occurred to size 1.5 throughout the storm, with most avalanches from north and west facing slopes due to strong southerly winds.
Explosive control produced the same results, with remotely triggered slab avalanches up to 300 m away indicating touchy conditions.
We expect slabs to continue to be reactive to human triggers.
Snowpack Summary
20-30 cm of recent storm snow has been redistributed by strong winds to deeper deposits on north and east facing slopes. Low elevations may have a surface crust from warm temperatures and rain.
A spotty layer of surface hoar can be found around 25-45 cm deep in sheltered terrain features at and below treeline. The distribution of this layer is not well known.
A layer of facets buried at the end of November can be found 100 to 200 cm below the surface. The snowpack depth varies between 150 and 250 cm at treeline.
Weather Summary
Friday Night
Cloudy with flurries, westerly winds 30-40 km/h. Freezing levels at valley bottom.
Saturday
Mainly cloudy with 3-7 cm of snow, southerly winds 40-60 km/h. Freezing levels rise to 500 m, treeline temperature -5 °C.
Sunday
Mainly cloudy and up to 5 cm of snow. Southerly winds, 60-90 km/h. Freezing levels remain around 500 m. Treeline temperatures near -5 °C.
Monday
Mostly cloudy with possible flurries and southerly winds, 60-80 km/h. Freezing levels rise towards 1000 m, treeline temperatures around -3 °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.
- Avoid rock outcroppings, convexities, and anywhere the snowpack is thin and/or variable.
- Closely monitor how the new snow is bonding to the old surface.
Problems
Wind Slabs
Reactivity may linger, especially where slabs sit over a layer of surface hoar.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A deeply buried layer of facets sitting on a hard crust 100-200 cm below the snow surface is likely unreactive. It may be triggered from a thin spot or by a very heavy load such as a cornice failure.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 23rd, 2023 4:00PM
