We expect another natural avalanche cycle to occur starting Friday night and tapering off late on Saturday. Avoid all avalanche terrain during this time! Ski resorts and non-avalanche terrain are the places to enjoy the fresh snow right now.
Weather Forecast
Friday night and Saturday morning could see as much as 15 to 20 cm of snow in our forecast area along with moderate to strong SW winds. Later in the day we expect to see both the precipitation and winds decrease as the temperatures cool. Sunday and Monday look like scattered flurries, cool temperatures and light winds.
Snowpack Summary
10-15 cm of new snow Friday with strong SW alpine winds. The main concern in the snowpack continues to be the three persistent weak layers of surface hoar and/or facets that are found between 50 and 100cm down in the snowpack. We continue to observe sudden test results, whumphing and large propagations on these layers. Below this is a faceted base.
Avalanche Summary
Some natural activity observed Friday with a size 2.5 avalanche over Cascade Falls in Banff and some natural avalanches on Mt Stephen in Yoho but visibility was poor. Big avalanches with explosives over the last few days show that snowpack remains prime for triggering. Some avalanches ran full path and put dust or debris on roads.
Confidence
Forecast snowfall amounts are uncertain on Saturday
Problems
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.
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.