Regions
Banff Yoho Kootenay.
We should get a small storm on Friday which will refresh ski conditions, but not enough to change the avalanche danger greatly. Remain vigilant with routefinding below treeline where the Dec. 3rd Surface Hoar may be lurking!
Weather Forecast
The ridge of high pressure will start to break down Friday morning. Friday afternoon into Saturday morning, a system will dump 5-10 cm at upper elevations with winds switching to moderate from the SW and freezing levels staying at valley bottom. Saturday and Sunday will be partly cloudy with light precipitation and light west winds.
Snowpack Summary
In sheltered terrain between 1700 and 2150m, 30-40 cm of facetted snow sits over the December 3rd surface hoar. Easy to moderate shears found on this interface. No other significant shears have been observed in the snowpack. There is approximately 1 meter of snow at treeline,
Avalanche Summary
No new avalanches observed in the last few days.
Confidence
Due to the number and quality of field observations
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.