The Columbia Icefield Parkway will be closed until Sunday March 19 at the earliest due to avalanche conditions. Check alberta511.ca for updates.
Weather Forecast
Temperatures cooling and freezing levels dropping to valley bottom for Friday with a clearing trend. Winds from the SW increasing on Friday. Light scattered snowfall Friday, increasing in intensity over the weekend, with an additional 20cm expected.
Snowpack Summary
20cm of new snow has arrived in the past 24 hours. This soft storm slab is bonding poorly to the old snow surface. The mid-pack consists of persistent slab layers intermixed with weak facets. The base is weak facets, depth hoar, and an ice crust from November. New windslabs forming with increased winds.
Avalanche Summary
Avalanche control work on the Icefield Parkway produced numerous slab avalanches to size 2.5, but control efforts were limited by weather. One large natural size 3.5 was observed in the alpine near Sunwapta - East aspect, 2700m and ran on the ground (deep persistent basal weakness). Numerous large natural avalanches were observed up Maligne.
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.