Avalanche control work is planned along Highway 93 on Thursday, January 9th from 12:00pm to 4:30pm. Travelers on Highway 93 north can expect delays of one to two hours at a time between Parker Ridge and just north of Saskatchewan Crossing.
Weather Forecast
A few flurries and light to moderate SW winds should do little to change the current avalanche hazard in the next 24 hours.. More snow and stronger winds are forecast for the end of the week and will result in an increase in the hazard ratings.
Snowpack Summary
Last weekends storm snow overlies existing wind slabs which in many places has a very weak faceted basal layer. Below tree line the snow pack has very little support except in isolated open areas where wind slabs may exist. Our field team experienced extensive whumphing whilst out ski touring today.
Avalanche Summary
The natural cycle of avalanches has tapered off now but the lingering basal instability is still very much a factor as evidenced by the numerous avalanches triggered by Marmot ski patrol in their explosive control runs recently.
Problems
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.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.