Avalanche Forecast
Issued: Dec 6th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
wlewis,
Avalanche Canada
Keep decision making conservative, especially in areas that received no rain.
Fresh snow sits over a weak and reactive surface hoar layer. Head to simple terrain, free from overhead hazard.
Summary
Confidence
Moderate
Avalanche Summary
A widespread natural cycle occurred yesterday, with storm slabs to size 2, and wet avalanches where rain saturated the snowpack. Avalanches ran on a buried surface hoar layer or on the old snow interface. Several large remotely triggered avalanches were reported on the buried surface hoar, indicating very touchy conditions.
Activity is expected to decrease as it cools, and surface crusts form from the recent rainfall.
Snowpack Summary
By Thursday morning around 50 mm of precipitation (rain and/or snow) has fallen during this storm. At higher elevations, deeper and more reactive slabs can be found north and east-facing slopes. This snow likely sits over a crust from rainfall at lower elevations in all areas, and where rain fell at higher elevations.
The layer of greatest concern, large surface hoar, can be found buried 30-70 cm deep. On steep south-facing slopes, this surface hoar sits on a thin sun crust.
The mid-pack is generally well-settled. Lower in the snowpack a crust with weak facets beneath it can be found 20 cm off the ground.
Weather Summary
Wednesday Night
Cloudy with freezing levels between 1000-1500 m. 10-25 cm of snow is possible above, favouring the West Purcells and terrain south of Highway one. Southwesterly winds, 15-30 km/h.
Thursday
Mostly cloudy, up to 10 cm of snow is possible in the east of the region as the front exits. Freezing levels sit around 1000, treeline temperatures around -5 °C.
Friday
Freezing levels drop to valley bottom. A mix of sun and cloud, with westerly winds 10-30 km/h. No snowfall expected. Treeline temperatures around -8 °C.
Saturday
A mix of sun and cloud with light snowfall possible. Freezing levels sit at valley bottom, treeline temperatures around -8 °C. Southwest winds increase to 60 km/h.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Remote triggering is a concern, watch out for adjacent and overhead slopes.
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Storm Slabs
Slabs will be most reactive where they sit on a layer of buried surface hoar (think convex rolls, sheltered treeline terrain) and around ridgelines, where winds deposited snow. New slabs may form above the crust created by the recent rain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 7th, 2023 4:00PM
