Regions
Banff Yoho Kootenay.
A storm is coming, but most of the precip is coming later in the day Tuesday, so not much change until Wednesday. This new snow will be great for ski conditions, but will make for touchy avalanche conditions as it lands on a weak base
Weather Forecast
Finally, snow is in the forecast! We should see light snow starting on Tuesday with only small accumulations ~ 5cms. An additional 10-15 cms by Wednesday PM and up to 40 cms by Thursday. The greatest amounts will be west of the divide. Temperatures should remain cold throughout, but winds will be strong W/SW with the highest on Tuesday and Thurs
Snowpack Summary
A cm or two of new snow is covering up widespread surface hoar and facets in most places. In exposed alpine areas, old wind slabs 10-40 cm deep linger in immediate lees. The October 26th crust/facet layer is ~30 cm above ground. In many areas the entire snowpack is faceting and becoming quite weak. Snow depths range from 50-85 cm at 2000 m.
Avalanche Summary
No new avalanches reported or observed today, but as recently as Saturday someone triggered a nasty looking size 2 on the SE slopes of Cirque Fore-Peak at 2700m above Helen Lake. Two skiers were caught on the flanks of a slab 20-40cm deep, 80m wide, running up to 250m with no burial but they some lost equipment.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
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.
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.