Avalanche Forecast
Issued: Dec 23rd, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Storm Slabs.
mconlan,
Avalanche Canada
The snowpack may take a while to equilibrate to the recent snow load. Conservative terrain travel is essential at this time until we have clear evidence that buried weak layers have stabilized.
Summary
Confidence
Moderate - Uncertainty is due to how buried persistent weak layers will react with the forecast incoming weather.
Weather Forecast
WEDNESDAY NIGHT: Clear skies, 20 to 40 km/h west wind, alpine temperature -5 C.
THURSDAY: Clear skies, 20 to 40 km/h southwest wind, alpine temperature -4 C.
FRIDAY: Mostly cloudy, 20 km/h south wind, alpine temperature -3 C.
SATURDAY: Cloudy with snowfall, accumulation 5 cm, 20 km/h south wind, alpine temperature -6 C.
Avalanche Summary
Many storm and persistent slab avalanches were observed on Tuesday, occurring in many areas across the region. They were generally large (size 2), on west, north, and east aspects, 20 to 70 cm thick, and between 2000 and 2300 m. The likelihood of triggering the layers described in the snowpack summary remains.
Snowpack Summary
A hefty storm impacted the region Monday, with around 30 to 40 cm of snow accumulation. Strong wind accompanied the storm, blowing from variable directions. Expect to find storm and wind slabs across the region until they bond to the snowpack.Â
This snow is loading two weak layers around 50 to 100 cm deep. The layers are composed of feathery surface hoar and sugary faceted grains and they overly a hard melt-freeze crust. There has already been substantial avalanche activity on this layer from natural and human triggers. This layer remains a major concern, as humans may be able to trigger large and destructive avalanches on it. There has been less avalanche activity reported west of Castlegar but a similar snowpack exists so the possibility remains for human triggering.
Another crust with associated faceted grains may be found near the base of the snowpack. There haven't been recent avalanches reported on this layer but it remains on our radar. The most likely place to trigger it would be from shallow, rocky terrain.Â
Terrain and Travel
- Make conservative terrain choices and avoid overhead hazard.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Give the new snow time to settle and stabilize before pushing into bigger terrain.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Problems
Persistent Slabs
Weak layers of surface hoar and/or faceted grains overly a hard melt-freeze crust around 50 to 100 cm deep. The likelihood of triggering these layers will remain likely as it stabilizes from the load that was recently added on it.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
The recent 30 to 40 cm of snow may take a bit longer to bond to the snowpack. The snow fell with strong and variable wind, so deep and touchy deposits are likely found near ridges too. Don't let good visibility lure you into dangerous avalanche terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 24th, 2020 4:00PM
