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.
Another day of temperature inversions and solar heating will keep slabs sensitive to failure on Tuesday.
Weather Forecast
Continued warm temperatures and sun are expected Tuesday as the temperature inversion continues . Winds that have been in the moderate range out of the West are forecast to diminish through to Wednesday. Cooling is expected on Wednesday increasing cloud. Trace amounts of snow can be expected Thursday.
Snowpack Summary
New solar crusts steep South and West slopes. Extensive wind effect in the alpine, less so at treeline. In thick snowpack areas, the Dec 10th weak layer of facets is now down 100-150cm with a stronger snowpack below. In thin snowpack areas, there is little separation between Dec 10 and the weak depth hoar/ facets sitting 40 cm above the ground.
Avalanche Summary
A size 3 slab failed on the south aspect of Mt Fairview sometime during the last couple days of temperature inversions and clear skies. The crown was 70cm to 1m deep and over 1000m wide. The slide ran up the other side of the valley below Sheol. There were 2 sz 2 loose wet avalanches observed on a field trip to Hamilton Lake at 2400m west aspect.
Confidence
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.