Avalanche Forecast
Issued: Jan 10th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
mconlan,
Avalanche Canada
New slabs are likely to be touchy to riders and the snow will load buried weak layers that recently produced destructive avalanches. Now is the time to adopt a conservative mindset and give the snowpack time to stabilize.
Summary
Confidence
Weather Forecast
SUNDAY NIGHT: Cloudy with snowfall, accumulation 5 to 15 cm with the most in the west of the region, 40 km/h southwest wind, alpine temperature -4 C.
MONDAY: Cloudy with snowfall then clearing, accumulation 10 to 20 cm, 30 km/h southwest wind, alpine temperature -4 C.
TUESDAY: Cloudy with snowfall, accumulation 30 to 50 cm, 40 km/h southwest wind, alpine temperature -2 C.
WEDNESDAY: Cloudy with snowfall, accumulation 20 to 40 cm, 30 km/h southwest wind, alpine temperature -6 C.
Avalanche Summary
A large (size 3) avalanche was remotely triggered by skiers on Cowboy Ridge near Whistler on Saturday. The avalanche occurred on a north to northwest aspect at around 1900 m. The crown ranged reached up to 200 cm and was approximately 200 m wide. Check out this MIN for photos and more information. A similar avalanche was remotely triggered by skiers on a nearby westerly slope on Thursday; check out this MIN for more info and photos.
These avalanches are clear evidence that the weak layers described in the Snowpack Summary are still triggerable by riders and the consequence of being caught would be high.
Otherwise, small storm and wind slab avalanches were triggered by riders and naturally on Saturday and Sunday, generally 10 to 30 cm deep, on north to northwest aspects, and at treeline and alpine elevations.
Snowpack Summary
New storm and wind slabs will form during Sunday night into Monday's storm. The storm is expected to drop around 15 to 30 cm of snow, with the most in the west of the region. The storm will come with strong southwest wind so wind slabs are expected at higher elevations.
The snowpack is currently quite complex. Numerous layers of surface hoar may be found in sheltered terrain in the top 100 to 150 cm. The area of greatest concern is around 100 to 200 cm deep, where surface hoar or sugary faceted grains may sit above a hard melt-freeze crust from early December. There have been several recent large natural and human-triggered avalanches on this layer, particularly around Whistler and Pemberton.
Near the base of the snowpack there may be faceted grains above a crust from early-November, which was identified as the failure layer in recent sporadic large avalanche releases.
Terrain and Travel
- Watch for fresh storm slabs building throughout the day.
- Be careful as you transition into wind affected terrain.
- Make conservative terrain choices and avoid overhead hazard.
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Storm Slabs
New storm and wind slabs are expected to build during Sunday night's storm, which may be touchy on Monday. Avoid being lured into committing avalanche terrain during clear periods on Monday.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A couple of problematic layers may be found around 100 to 200 cm deep, including weak layers of surface hoar and faceted grains above a hard melt-freeze crust. A few high-consequence avalanches have been triggered by riders in the past few days near Whistler.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 11th, 2021 4:00PM
