Avalanche Forecast
Regions: South Rockies.
Staying safe involves selecting sheltered terrain away from wind-affected snow. As a bonus, this is also where the best riding will be found.
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
Wednesday night: Flurries. Moderate southwesterly winds. Freezing level around 1000 m.
Thursday: Flurries. Strong southwesterly winds. Freezing level rising to around 1500 m in the afternoon.
Friday: Around 4 cm new snow. Moderate southwesterly winds. Freezing level around 1800 m.
Saturday: Around 4 cm new snow. Moderate southwesterly winds. Freezing level around 1600 m.
Avalanche Summary
On Monday we received reports of natural and explosive triggered wind slab avalanches size 1.5-2.
On January 16th, a natural size 2 wind slab stepped down to the deep persistent basal facets below a rock band, details here.
Snowpack Summary
Recent strong westerly winds have formed stiff wind slabs in exposed terrain at treeline and alpine locations. A crust can be found at lower elevations and on solar aspects due to recent daytime warming and sun exposure.
A well consolidated mid-snowpack overlies a generally weak basal snowpack. The bottom 10-20 cm of the snowpack consists of facets and deteriorating crusts. There is potential for this deep persistent layer to reawaken in the warm alpine temperatures later in the week.
Terrain and Travel
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Extra caution for areas experiencing rapidly warming temperatures for the first time.
Avalanche Problems
Wind Slabs
Strong southwesterly winds have blown recent snow into stiff wind slabs in lee features at alpine and treeline. Human triggering of wind slabs is possible.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Deep Persistent Slabs
As temperatures trend warmer and freezing levels rise, there is potential for the deep basal weak layers to become active. Deep persistent slab avalanches on these layers are most likely to be triggered from shallow snowpack areas near rocky outcroppings.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3