Avalanche Control along the Icefields Parkway is planned for Friday 1100 - 1700, expect delays.Strong winds and 20cm+ of snow have created dangerous avalanche conditions.
Weather Forecast
The storm has ended but periods of light snow can be expected over the weekend. Alpine temps are forecasted to drop to -16 overnight and with a high of -12. Winds will be blowing moderate from the SW, gusting to strong. Temps will gradually rise until mid next week.
Snowpack Summary
30-40cm of snow within the past 36hrs with moderate to strong SW winds is building slab at treeline and above. A reactive storm slab can be found at all elevations and aspects. The upper snow pack has several touchy surface hoar and facet layers which are now buried 40-50cm and 60-80cm. The mid-pack is facetted and weak, with depth hoar at its base
Avalanche Summary
A widespread Na cycle up to Sz 2.5 on all aspects and elevations today along the Parkway. Poor visibility into the high alpine.While accessing a short and steep slope adjacent to the highway, an avalanche technician triggered the storm slab resulting in a full burial with no injuries.
Confidence
Wind speed and direction is uncertain on Saturday
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.