Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
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 unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Jasper.
While the new snow will refresh ski conditions, it will also bring the danger rating back up. Watch out for rapid loading with extreme winds on Saturday.
Weather Forecast
Up to 25cm of snow on Saturday. Temperatures are expecting to rise to -5 in the alpine and freezing levels to valley bottom through the day. Also, west winds are going to pick up to extreme in the alpine and strong at treeline and below. A detailed mountain weather forecast is available from Avalanche Canada.
Snowpack Summary
New snow is forecast to fall on top of a settled snow in sheltered areas and wind pressed in exposed locations and near ridge crests. This will likely create a slab avalanche problem to watch. Below this the Dec. 11th persistent weak layer is buried 50-100cm. The deep persistent weakness lingers near the ground in the depth hoar and facets.
Avalanche Summary
Small avalanches have been failing to ground in facets in the last couple of days. However we haven't seen any large natural activity since last weeks storm which initiated several deep releases from the alpine up to size 3.
Confidence
Intensity of incoming weather systems is uncertain on Saturday
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.
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.
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.