Regions
Banff Yoho Kootenay.
The weaker basal depth hoar/facets aren't going anywhere in a hurry. We still have low confidence in shallow or variable snowpack areas. Travel conditions are excellent. SH
Weather Forecast
Temperatures will start to creep up Sunday but we will stay in a light Northerly flow. A mild inversion (alpine temps still below freezing) will enter the region Sunday night into Monday with mainly sunny skies.
Snowpack Summary
A well settled upper snowpack with highly variable depths sits over the ever present weak facets and depth hoar in the bottom half of the snowpack. Colder temperatures have helped the slab bridge over the weaker base. On Saturday, strong to extreme North winds up Hwy 93N formed thin wind slabs in the lees of ridge crests and gully features.
Avalanche Summary
No new avalanches were observed or reported today.
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.