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.
Thinner snowpack areas within the Little Yoho region are the main concern. In these areas human triggering of the basal facets is still possible. Probe often to help determine snow depths and assess the strength of the lower snowpack.
Weather Forecast
Temperatures will increase slightly on Tuesday but remain near -10 C at treeline. Winds will pick up out of the SW on Tuesday morning, becoming strong by late afternoon. A few cm's of snow is expected but accumulations will be limited. On Wednesday winds are expected to calm down, with 5-10 cm snow arriving before a clearing trend begins Thursday.
Snowpack Summary
5-15 cm of snow sits over the Jan 17 layer of surface hoar, or sun crust. Thin wind slabs can be found in alpine lee areas from strong SW winds on Saturday. Of greatest concern are the weak facets and depth hoar at the base of the snowpack. In thinner snowpack areas (i.e. less than 150 cm deep) triggering a slab on these facets is more likely.
Avalanche Summary
Little natural avalanche activity has been observed over the last week. A group in the Emerald Lake area triggered a wind slab on Saturday in lee alpine terrain, and a group on Dolomite Shoulder triggered a slab on the basal facets on Sunday. Small wind slabs have been triggered by control work at the local ski hills in the last few days.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Wednesday
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.