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
Make conservative terrain choices. Recent storm snow and buried weak layers may be reactive to human triggering.
Reduce your exposure to avalanche terrain if the temperature is above 0°C.
Summary
Confidence
Avalanche Summary
On Sunday, explosive control in the Monashees produced a size 2 storm slab at treeline. A MIN report from Yanks Peak describes a remotely triggering avalanche from the base of a concave feature.
Natural avalanche activity has tapered, but human-triggered avalanches remain possible at higher elevations, particularly where slabs sit over the weak surface hoar.
Whumpfing has been observed throughout this region - this is a sure sign of instability on a buried weak layer!
Snowpack Summary
The recent 30-40 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 to ridgeline in most areas.
A layer of surface hoar is now buried 50-80 cm deep. The recent rain crust is thought to limit avalanches on this persistent weak layer. However, it may be possible to trigger this in isolated terrain features, or for small avalanches to step down to this layer.
The lower snowpack is a mix of rounded and faceted grains. 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 southwest. Treeline temperature around -5 C.
Wednesday
A mix of sun and cloud. Alpine wind 40 to 90 km/h from the southwest. Treeline temperatures around -4 C .
Thursday
Cloudy with snowfall, 5 to 10 cm of accumulation. Alpine wind 10 to 30 km/h from the southwest. Treeline temperature around -7 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Extra caution for areas experiencing rapidly warming temperatures for the first time.
- Use careful route-finding and stick to moderate slope angles with low consequences.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
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
Buried surface hoar is most likely to be found at treeline elevations, and most triggerable where the recent rain crust thins, or disappears.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 12th, 2023 4:00PM
