Avalanche Forecast
Issued: Dec 22nd, 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 substantial load that was added to it. 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 quickly the snowpack will recover and gain strength.
Weather Forecast
TUESDAY NIGHT: Clear skies, 20 to 40 km/h northwest wind, alpine temperature -10 C.
WEDNESDAY: Mix of sun and cloud, 20 to 40 km/h northwest wind, alpine temperature -7 C.
THURSDAY: Clear skies, 20 km/h southwest wind, alpine temperature -3 C.
FRIDAY: Mix of sun and cloud, 20 km/h south wind, alpine temperature -3 C.
Avalanche Summary
Early reports on Tuesday found large storm slab avalanche activity within Monday's storm snow, generally out of alpine terrain. It is anticipated that a natural avalanche cycle occurred during the storm on Monday night. Photos in this MIN show a close-up of how dangerous the snowpack is right now. Expect human-triggered avalanches to be likely to occur on Wednesday as the snowpack equilibrates to the new load.
Snowpack Summary
A hefty storm impacted the region Monday and Monday night, with around 30 to 40 cm of snow accumulation. Strong wind accompanied the storm, blowing from the south, west, and north. Expect to find storm and wind slabs across the region. The snow will likely take a few days to bond to the snowpack.
This snow is loading weak layers around 50 to 100 cm deep. The layers may be composed of feathery surface hoar and/or 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.
Another crust with associated faceted grains may be found near the base of the snowpack. There have been no 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. Monday's storm snow is loading these layers. The likelihood of triggering these layers will remain likely as it stabilizes with the load that was added to it.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
The recent 30 to 40 cm of snow will take some time to stabilize. 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 23rd, 2020 4:00PM
