Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Banff Yoho Kootenay.
The structure of this early season snowpack is poor and will remain very sensitive to snow riders for the next several weeks to come. Conservative terrain selection and minimizing your exposure to a nasty ride is the name of the game these days. PJ
Weather Forecast
The forecast temperature going into next week will be another warming trend with freezing levels rising to Treeline elevation by Tuesday and into Wednesday. Accompanying this Southwest flow will bring light precipitation and strong winds in the Alpine.
Snowpack Summary
Warmer daytime temperatures this weekend are promoting settlement of the upper snowpack and creating more of a slab over the basal facets especially in wind affected areas. The lower half of the snowpack is poorly structured, with facets (Nov 24th) below the recent storm snow, thin crusts (Nov 6th) below this, and then depth hoar near the ground.
Avalanche Summary
Skier triggering is still high in likelihood particularly coupled with the recent daytime warming. Two size 2 skier accidentals were triggered this afternoon just outside ski area boundaries around Sunshine and Lake Louise back country. This reaffirms the weak basal layers persist and remain prone to human triggering so very little has changed.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Tuesday
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.