Avalanche Forecast
Issued: Jan 23rd, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
ahanna,
Avalanche Canada
The MODERATE rating is not intended to be a green light for committing terrain. Natural avalanche activity has largely subsided though human triggered avalanches are still possible.
Summary
Confidence
Moderate - Confidence is due to a stable weather pattern; little change is expected for several days. Uncertainty is due to the fact that deep persistent slabs are particularly difficult to forecast.
Weather Forecast
Thursday night: Flurries. Moderate to strong southwesterly winds. Freezing level around 1500 m.
Friday: Up to 5 cm new snow. Moderate to strong southwesterly winds. Freezing level around 1500 m.
Saturday: Flurries. Light southwesterly winds. Freezing level around 1500 m.
Saturday: Flurries. Light southwesterly winds. Freezing level around 1500 m.
Avalanche Summary
No new avalanche observations in the previous 3 days. 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 alpine and treeline. 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 this 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.
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
Expected Size
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
Expected Size
Valid until: Jan 24th, 2020 5:00PM
