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.
Regions
Banff Yoho Kootenay.
http://www.pc.gc.ca/apps/scond/Cond_E.asp?oID=26206&oPark=100092Natural activity has slowed with the cooling temperatures, but tricky and dangerous avalanche conditions exist. The potential to trigger large avalanches is very real.
Weather Forecast
Sunday looks to be mainly cloudy with a few cm possible and mainly light SW winds. Freezing levels to 1700m. Light snow in the forecast over the next few days with and continued light winds.
Snowpack Summary
40-60 cm of snow in the past week combined with moderate SW winds created windslabs on lee and crossloaded features. This rests on hard windslabs at treeline and above which overlie a structurally weak snow pack. Below 1900m a surface crust has formed from previous rain and warm temperatures, followed by subsequent cooling.
Avalanche Summary
A size 3 on the W face of Noseeum peak (Hwy 93 N) was reported to have run in the last 12 hours, stepping to ground. 2 large avalanches outside the Lake Louise and Sunshine ski area boundaries reported yesterday also stepped down to ground. Smaller wind slabs to size 1.5 in the alpine are still being triggered, although harder to initiate today.
Confidence
Due to the number of field observations on Saturday
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.