Regions
Banff Yoho Kootenay.
With Christmas just around the corner, it's obvious that everyone has been well behaved girls and boys, as Santa has delivered us The Green Brick (3 x Low for all three days) as a gift for the season. Enjoy the amazing backcountry conditions!
Weather Forecast
The awesome NW flow continues. This is a great upper level (5400m) flow because it's the pathway for carrying cold, moist storm systems into our mountains. However, despite this nicely aligned pathway, there is nothing coming down the pipe for a few days, and Xmas looks to be cold and stable with no new snow in the forecast until at least the 26th.
Snowpack Summary
A well settled snowpack with few weaknesses exists throughout the region with the upper 20 cm comprised of low density powder with no slab. The exception might be high elevation (above 3000m) leeward slopes. Below treeline the Dec 3 layer of surface hoar remains visible and produces hard, but planar test results. This weakness is strengthening.
Avalanche Summary
No new natural slab avalanches have been observed today, except sluffing in really steep terrain due to the low density surface snow.
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.