Avalanche Forecast
Issued: Jan 6th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
shorton,
Avalanche Canada
Dangerous avalanche conditions exist on wind loaded slopes and steep rocky terrain.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack. Uncertainty is due to the complexity of the snowpack’s structure.
Weather Forecast
WEDNESDAY NIGHT: Flurries with 5-10 cm of snow, moderate southwest wind, treeline temperatures around -8 C.
THURSDAY: Cloudy with isolated flurries and up to 5 cm of snow, strong southwest wind, treeline temperatures around -5 C.
FRIDAY: Mix of sun and cloud, moderate southeast wind, temperatures around -10 C.
SATURDAY: Cloudy with isolated flurries and trace accumulations of snow, moderate south wind, temperatures around -8 C.
Avalanche Summary
Since New Year's there have been steady reports of natural wind slab avalanches in alpine terrain (size 1-2), and some smaller human-triggered wind slab avalanches in lee terrain (size 1). There are good photos of these avalanches in recent MIN reports (e.g. here, here, here, and here). While there have been no reports of persistent slab avalanches since Dec 22, there have been reports of large whumpfs in the Hudson Bay, Hankin, and Babines area over the past few days, suggesting the buried weak layers are still possible to trigger.
Snowpack Summary
Strong wind is moving around 40-60 cm of snow that has fallen since New Year's Day. Reactive wind slabs can be found in exposed open terrain, while lower density snow can be found in sheltered terrain. In some parts of the region this snow could be sitting above a surface hoar layer and forming isolated storm slabs on steep rolls in sheltered areas.
The lower snowpack has two crusts with potentially weak snow around them. Reports from the Smithers area suggest the upper crust is 60-90 cm below the surface and has shown signs of being possible to trigger from shallow areas. The other crust is near the bottom of the snowpack, and may be possible to trigger from shallow rocky slopes.
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Choose slopes that are well supported and have limited consequence.
- Be especially cautious near rock outcroppings, on steep convexities and anywhere the snowpack feels thinner than average.
Problems
Wind Slabs
Intense wind from the south has left touchy slabs in leeward terrain. Most of the wind loading should be on northeast slopes, but shifting winds over the past few days may have left unstable slabs on all aspects. In some isolated sheltered areas recent snow may be settling above surface hoar.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Triggering large avalanches on weaknesses in the lower snowpack remains a possibility. In some areas the concern is weak snow around crusts 60 to 90 cm deep, while in others it is weak snow near the bottom of the snowpack. This problem is best managed by avoiding steep rocky slopes and approaching challenging and complex avalanche terrain with extra caution.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 7th, 2021 4:00PM
