Avalanche Forecast
Issued: Dec 3rd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
dsaly,
Avalanche Canada
Keep your head up as you transition into open terrain at upper elevations, especially where wind impacts loose, dry snow. Be mindful that travel may be the most hazardous part of your day.
Summary
Confidence
Weather Forecast
FRIDAY NIGHT: Increasing clouds and flurries. South-southwest winds increasing overnight 15-30 km/hr. Alpine low temperature -12 C. Freezing level dropping to valley bottom.
SATURDAY: Flurries starting overnight, up to 15 cm accumulation through the day. Increasingly gusty west wind, 25-35 km/hr. Alpine high temperature -5 C. Freezing level below 1000 m.
SUNDAY: Partly cloudy with sunny breaks. Northwest-west wind, 15-30 km/hr. Alpine high temperature -7 C. Freezing level valley bottom.
MONDAY: Mostly cloudy with flurries, trace to 5 cm accumulation. Variable wind 10-20 km/hr. Alpine high temperature -9 C. Freezing level valley bottom.
Avalanche Summary
On Thursday, Dec 2, explosives triggered size 1-2 avalanches above 1800 m, with the larger (size 2) avalanches reported above 2000 m and included cornice failures triggering slopes below.
On Wednesday, Dec 1, explosives triggered size 1 loose wet and storm slab avalanches near Revelstoke. Evidence of a large and widespread natural avalanche cycle (up to size 3) was reported around the region. Additionally, neighboring region Glacier National Park reported a widespread natural avalanche cycle and produced up to size 3.5 avalanches with explosive control.
The recent atmospheric river onslaught brought heavy precipitation, strong winds and warm weather consistently produced multiple cycles of avalanche activity up to size 3. Widespread natural cycles were observed following each wave of the storm, with avalanches frequently running full path to valley bottom. The most recent reports of these natural avalanches were from Dec 1.
Snowpack Summary
The snowpack is drying and cooling after last weeks deluge of rain. A dusting of up to 10 cm fresh snow overlies a mostly supportive crust.
The mid-November crust is up to 5cm thick and found down 70-150 cm with faceting below the crust. The lower snowpack contains several early season crusts which appear well bonded.
Snowpack depths range from 120-250+ cm at treeline and alpine elevations, while below 1600m the snowpack decreases rapidly with elevation.
Terrain and Travel
- Be especially cautious as you transition into wind affected terrain.
- Carefully monitor the bond between the new snow and old surface.
- Approach lee and cross-loaded slopes with caution.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
Problems
Wind Slabs
Large wind slabs have developed over the last week with heavy snowfall and winds affecting treeline and alpine terrain. Recent strong to extreme winds developed slabs lower in the slope than usual. Fresh slabs may form Saturday as increasing winds impact new flurries and any loose, dry snow.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 4th, 2021 4:00PM
