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.
http://www.pc.gc.ca/apps/scond/Cond_E.asp?oID=26206&oPark=100092 Tricky and dangerous avalanche conditions exist. The potential to trigger large avalanches persists. Conservative route choices are recommended.
Weather Forecast
Saturday will be mainly cloudy with some isolated flurries. Freezing levels will drop to surface tonight and rise to 1500 m for Saturday through to Sunday. Flurries predicted to continue through the weekend with light South wind. Freezing levels may hold around 1500 m with light showers expected below this elevation.
Snowpack Summary
40-60 cm of snow in the past week combined with moderate SW winds has created new reactive windslabs on lee and crossloaded features. This rests on hard windslabs which overlie a structurally weak snow pack. Test results show sudden planner failures in the storm snow and basal depth hoar Below 1800 m the snowpack is moist from rain event on Thur.
Avalanche Summary
In the last 24 hrs, two large avalanches outside the Lake Louise and Sunshine ski area boundaries and stepped down to the ground. Skihills reported several smaller windslab avalanches near ridgetops. A Skier triggered a size 2.5 avalanche on Lipalian 2 (west aspect) outside Lake Louise ski area occurred on Wednesday.
Confidence
Freezing levels are 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.