Regions
Banff Yoho Kootenay.
Touchy avalanche conditions continue. Now is the time to avoid all avalanche terrain.Avalanche control will be conducted on Mt. Stephen and Mt. Dennis on Wednesday. Please no skiing or climbing in these areas.
Weather Forecast
Another sunny day on Wednesday with freezing levels around 1800 m. Cooler temperatures and some isolated flurries forecast for Thursday and Friday.
Snowpack Summary
85-100cm of storm snow has fallen in the Sunshine, Kootenay and Yoho areas, with 40-60cm around Lake Louise and Bow Summit since Mar 2nd. This storm snow has overloaded the Feb 10th layer of facets, surface hoar and sun crust, and in thinner snowpack areas, the deeper basal facet layer, causing large, destructive avalanches with wide propagations.
Avalanche Summary
A widespread natural avalanche cycle occurred in past 48 hours on all aspects and elevations. Two large remotely skier triggered avalanches were reported yesterday in the Lake Louise area. Natural cycle appears to be over but conditions remain very touchy and reactive to skier triggering.
Confidence
Due to the number and quality of field observations
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.