Avalanche Forecast
Issued: Dec 8th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
wlewis,
Avalanche Canada
Slabs will continue to be reactive as they sit over a problematic ice crust. Expect variable winds to have loaded unexpected features.
Give the snowpack time to gain strength before stepping into bigger terrain. Seek out sheltered, low angle terrain for the best riding.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
Snowfall tapers as the front exits today, replaced by scattered flurries and mixed cloud until a juicer system approaches this weekend.
WEDNESDAY NIGHT: Flurries continue with moderate west-southwest winds. Freezing levels drop to valley bottom.Â
THURSDAY: Cloudy with a chance of flurries, light westerlies. Freezing levels at valley bottom. Alpine highs of -8.Â
FRIDAY: Trace amounts of snow, most cloudy. Freezing level at valley bottom, alpine highs of -8. Light westerlies.Â
SATURDAY: Light to moderate snowfall starts early Saturday morning. Freezing levels climb to 1500m. Alpine highs of -3. Strong to extreme southwest winds.Â
Avalanche Summary
A natural size 2 wind slab was observed on Tuesday Dec 7 near Fernie, from a crossloaded treeline feature. Over the last three days, several size 1-1.5 wind slabs have also been skier triggered in immediate lees at treeline and above.Â
Numerous small loose dry avalanches have been observed out of steep sheltered terrain features.
All of these avalanches have been triggered on the new snow/ melt freeze crust interface. New snow is bonding poorly to the crust, creating tricky conditions in sheltered and wind affected areas.Â
Note there are very few field observations this early in the season. If you venture out into the mountains, please share your observations and/or photos on the Mountain Information Network!
Snowpack Summary
Recent storm snow sits over a thick and supportive melt freeze crust, 5-10cm thick on all aspects below 2400m. Moderate to strong westerly winds have created deeper deposits in lee features in the alpine and treeline.Â
The snowpack holds several early season crusts about 20-30cm above the ground. Last week's heavy rain saturated the snowpack and has begun to break down this crust at treeline and below, creating a cohesive lower snowpack.
Snowpack depths range from 10-80 cm at treeline elevations. The snowpack tapers quickly below 1800m, significantly diminished by the rain event.Â
Terrain and Travel
- Closely monitor how the new snow is bonding to the crust.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
Problems
Wind Slabs
Expect the bond between new snow and the rain crust to be poor, investigate conditions before exposing yourself to steep or exposed features. Deeper deposits will be found in wind loaded terrain features. Approach ridge crest and cross loaded features with caution.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 9th, 2021 4:00PM
