Avalanche Forecast
Issued: Dec 11th, 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.
zryan,
Avalanche Canada
Choose conservative terrain, weak layers in the mid and lower snowpack remain primed for human triggering.
Summary
Confidence
Avalanche Summary
Explosive control in the past few days has produced numerous wind slab and persistent slab avalanches up to size 2.
A remotely triggered slab was reported on a NE facing slope at 2300m in a shallow rocky area, also failing on the basal facets.
Natural avalanche activity has tapered since the storm, but human-triggered avalanches remain likely at treeline and above.
Snowpack Summary
The recent 30 cm of storm snow has likely been redistributed into deeper deposits on north and east facing slopes at higher elevations. This sits over a rain crust that has been observed up to 1900 m near Golden and 2200 m near Invermere.
A concerning layer of surface hoar is now buried 40-70 cm deep. A widespread natural cycle may have destroyed this layer in steep features but it likely still lingers unaffected features.
The middle and base of the snowpack holds large, weak snow crystals. A hard crust may be found near the ground.
Treeline snowpack depths are variable and generally range between 60 and 100 cm. Snowpack tapers rapidly as you move lower in elevation.
Weather Summary
Monday night
Mainly clear. Alpine wind light and variable. Treeline temperature around -9 C.
Tuesday
Mainly sunny with valley cloud. Alpine wind 15 to 30 km/h from the southeast. Treeline temperature around -5 C with an alpine temperature inversion in many areas.
Wednesday
A mix of sun and cloud. Alpine wind 25 to 50 km/h from the southeast. Treeline temperatures around -9 C .
Thursday
Cloudy with snowfall, up to 5 cm of accumulation. Alpine wind 10 to 30 km/h from the southwest. Treeline temperature around -9 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Make conservative terrain choices and avoid overhead hazard.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Stay off recently wind loaded slopes until they have had a chance to stabilize.
Problems
Wind Slabs
Recent winds have built reactive wind slabs in north and east-facing terrain features.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Surface hoar is most likely to be found at treeline elevations, and most triggerable where the rain crust (40-60 cm deep) disappears
Weak facets sit at the base of the snowpack, recent avalanches have failed on or stepped down to this layer
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 12th, 2023 4:00PM
