Avalanche Forecast
Issued: Jan 13th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Persistent Slabs and Loose Wet.
rbuhler,
Avalanche Canada
Hazard will likely depend on the extent of cooling and new crust formation Thursday night. Storm slabs are expected to remain touchy up high where the snow remains dry, especially in wind loaded terrain. Use extra caution around steep south facing slopes if the sun is strong.
Summary
Confidence
Moderate - Uncertainty is due to rapidly fluctuating freezing levels.
Weather Forecast
A ridge of high pressure brings dry and partly sunny conditions for Friday before a weak storm system arrives Friday night.Â
Thursday night: Mainly cloudy, light variable wind, freezing levels dropping to around 500 m.Â
Friday: A mix of sun and cloud, light SW wind, freezing levels reaching around 1500 m.Â
Friday night and Saturday: Snowfall up to 25 cm, moderate to strong SW wind, freezing levels reaching around 1300 m.
Sunday: Snowfall, light to moderate SW wind, freezing level reaching around 800 m.
Avalanche Summary
On Wednesday, natural avalanches up to size 3 were reported and natural dry loose avalanches up to size 2 were observed in extreme terrain. Several natural size 1 storm slabs were also reported failing down 15-20 cm as well as size 1 wet loose avalanches from steep below-treeline terrain. Skiers and explosives were also triggering a variety of avalanches. On Tuesday, a variety of natural avalanches up to size 3 were observed.Â
The early-December persistent crust/facet layer has been active in this region as recently as Sunday, producing avalanches up to size 3. This layer is still a concern in the region but the likelihood of an avalanche on this layer continues to decrease as temperatures drop following the warming event.Â
Snowpack Summary
On Thursday, freezing levels climbed to at least treeline. With temperatures expected to drop on Thursday night, a widespread surface crust is expected to form. Below the new crust, 40-60 cm of recent storm snow is settling rapidly with the mild temperatures. This recent storm snow overlies the January 10 interface which may include weak facets and/or surface hoar. Another layer of facets from early January can be found down 60-90 cm.Â
We're still actively monitoring the early December crust. In shallow spots it's down 90 cm while in wind-loaded terrain features it can be found as deep as 200 cm below the surface. It consists of faceted grains above a bulletproof crust formed by the Atmospheric Rivers of early December. There has been avalanche activity on this crust over the weekend. Larger avalanches in surface layers as well as natural cornice falls may still have potential to step down to this layer.
Terrain and Travel
- Choose conservative terrain and watch for clues of instability.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
- Avoid areas with overhead hazard.
Problems
Storm Slabs
A reactive storm slab should be expected where the snow surface remains dry and crust-free at higher elevations. They will be most reactive in wind loaded terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The early December crust can be found down 90 to 200 cm below the surface, with weak, sugary crystals (facets) on top of it. The likelihood of triggering an avalanche on this layer is decreasing but still remains a concern for avalanches stepping down. We are now in a low probability/high consequence scenario with this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
At lower elevations where the snow surface remains moist or wet, human triggered wet loose avalanches remain possible on steep slopes.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood
Expected Size
Valid until: Jan 14th, 2022 4:00PM
