Regions
Banff Yoho Kootenay.
Beautiful weather has us in a holding pattern. Backcountry users should monitor the weather stations and keep an eye on temperatures with the current inversion (cold in the valleys, warm up top), especially ice climbers. SH
Weather Forecast
The ridge will break down slightly for Saturday. There will still be an inversion with cooler valley temperatures and warmer in the in the alpine, although temperatures may not go quite as high above freezing as they did the last 2 days. Winds look to be in the light to moderate range. No snow is in the forecast for the next week.
Snowpack Summary
Sun crusts are developing on steep south slopes with a temperature inversion. Surface hoar up to size 20 has formed. Below 2500m, 30 - 50 cm of snow lies over the Nov 27th and Nov 23rd crusts. Both of these now overlie the Halloween crust/facet layer that sits 30-50cm above the ground.
Avalanche Summary
Given the heat in the alpine its a bit of a surprise there have been very few avalanches observed or reported at the time of writing, probably due to the short days this time of year. Some very small loose wet avalanches were noted up Hwy 93N on terrain that was in the sun, sheltered, and below steep cliffs (climbing terrain) up high.
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.