Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Regions
Little Yoho.
Not enough snow coverage for skiing at lower elevations in Little Yoho, so this bulletin is mostly based on observations from the Banff, Yoho & Kootenay region. Ice climbing in Field is just starting to happen...
Weather Forecast
A SW flow is bringing some precipitation our way. Models are showing 2-10 cm on Thursday and an additional 5 cm on Friday. Northern areas should see the highest snow amounts. Winds should ease to moderate from the SW with the incoming storm and then switch to NW with colder temps on Friday midday. Saturday looks colder and drier.
Snowpack Summary
15-30 cm of facetted surface snow with surface hoar forming at all elevations. Wind effect at treeline and above has scoured ridge crests and created wind slabs in the alpine. The Oct 26 crust is roughly 30 cm above the ground with facets above and below it. It is present up to 2800m on shady aspects, and at higher elevations on solar aspects
Avalanche Summary
A large avalanche was observed on the N face of Mt. Stanley. Forecasters on a trip into the lake louise backcountry on Tuesday had several whumphs in alpine and treeline areas that had been wind affected and remote triggered a size 2 on a NE aspect at 2300m that failed on facets near the ground
Confidence
Intensity of incoming weather systems is uncertain on Thursday
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.