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.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Jasper.
The storm snow is starting to settle in yet its still too early to be bold in the terrain. Use caution as localized slab development and analysis will be critically important for safe travel in the back-country.
Weather Forecast
Monday will be a mix of sun and cloud with isolated flurries, trace of snow, alpine high -13 °C, and ridge wind west at 20 km/h gusting to 45 km/h. Tuesday will be mix of sun and cloud, no precipitation, -21 °C to -12 °C, and wind southwest 20 km/h. A detailed mountain weather forecast is available from Avalanche Canada.
Snowpack Summary
Jan 2-4, up to 45cm of snow arrived along the 93N. Moderate-strong SW winds built fresh wind slabs in open terrain. The Dec. 11th layer (surface hoar and facets) persists down 60-150cm, and continues to produce avalanches in shallow snowpack areas.
Avalanche Summary
Jan 5th helicopter control on high and low targets produced numerous avalanches with one being a size 4 at Sunset Pass; burying the Icefields Parkway with significant debris and mature trees.
Confidence
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.