The Winter Permit System is now in effect. Be sure the area is open before you enter. Don't let the beautiful blue skies cloud your judgement today. Check the snow before dropping in.
Weather Forecast
The Arctic air has arrived, and temp's have dropped. Today, sunny weather will dominate, with light northerly winds and no precipitation in the next 4-5 days. Temp inversions are expected to develop over the next couple of days, with alpine temp's warming considerably while the valleys remain cool.
Snowpack Summary
Reverse-loading from strong northerly winds yesterday has created wind slabs on southerly aspects. These slabs overlie a variety of surfaces, including suncrust on steep S-SW aspects, with 2-3mm surface hoar on most other aspects. Below this, the snowpack as a whole is strengthening. A weak basal layer exists on alpine N/NE aspects.
Avalanche Summary
A skier-triggered size 2 from a SW aspect, at ~2200m, was reported in the McGill area yesterday: 30cm deep, 40m across, running 200m in length. Numerous natural-triggered size 2 to 3 slabs were observed from steep alpine terrain yesterday. These occurred during the strong northerly wind event and pulled out of north and south aspects.
Confidence
Due to the number of field observations
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.