Avalanche Forecast
Issued: Dec 19th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
rgoddard,
Avalanche Canada
Enjoy the fresh snow but don't let it lure you into unsafe terrain.
Wind-affected terrain may have produced fresh wind slabs. Buried weak layers are still triggerable.
Summary
Confidence
Moderate
Avalanche Summary
As of this writing, no new avalanches were reported in the last 24 hours. With recent low-density snow continuing to fall and winds picking up, expect this to change.
Persistent slab avalanche activity has continued to taper off but these layers will likely remain triggerable in specific terrain features.
Snowpack Summary
In the alpine and at treeline moderate to strong northwest winds have redistributed the recent low-density snow (up to 35 cm) and formed fresh wind slabs. On steep solar slopes, these new wind slabs and fresh snow will be sitting on a thin sun crust. In more sheltered areas, the new snow covers surface hoar and facets.
The snow further down is more settled and it may overlie another layer of surface hoar or thin sun crust, although it does not appear to be widespread. Both were formed in early December, and are now buried 50 to 60 cm deep.
The mid-November layer consisting of facets and surface hoar is now buried around 80 cm deep. These depths will vary throughout our region with decreased depths in the northern areas. At the bottom of the snowpack, a thick crust sits on the ground.
At treeline, snowpack depths vary from 100 to 200 cm.
Weather Summary
Monday Night
Cloudy with some clearing, up to 2 cm accumulation, 20 km/h west wind, -25 C at 1500 m.
Tuesday
Cloudy, 10 to 15 cm accumulation, 15 to 25 km/h east winds, -25 C at 1500 m.
Wednesday
Sunny with cloudy periods, no accumulation, 20 to 30 km/h northeast wind, temperature -30 C at 1500 m.
Thursday
Mostly sunny, no accumulation, 15 to 20 km/h north winds, -30 C at 1500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Closely monitor how the new snow is bonding to the old surface.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- In times of uncertainty conservative terrain choices are our best defense.
- Avoid open slopes and convex rolls at and below treeline where weak layers may be preserved.
Problems
Persistent Slabs
Two persistent weak layers can be found in the top meter of the snowpack. The first is a surface hoar/crust layer from early December and the second is a surface hoar, facet or crust layer from mid November. The most recent activity on these layers has been in the northern part of the forecast region. These layers are most concerning on sheltered treeline features where surface hoar is most likely to be preserved.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Sunday night saw moderate to strong northwest winds. The recent low density snow will be redistributed by these winds to form fresh wind slabs.
As more snow falls during the day on Tuesday, expect these slabs to build in wind exposed areas. In sheltered areas this snow will add to the unconsolidated snow on the ground and sluff management should be considered.
Aspects: North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 20th, 2022 4:00PM
