Regions
Banff Yoho Kootenay.
Storm slabs are expected to become touchy with additional snow on Sunday and Monday.
Weather Forecast
The storm will persist a bit longer. The forecast region is expecting up to another 10cm overnight, perhaps less in Western areas. Additionally, the temperature is going to dive down to -30 tomorrow, and creep back up later in the week. The wind will be variable in direction into the moderate range through Tuesday.
Snowpack Summary
Storm snow amounts are 10 to 30cm. This sits on harder wind pressed surfaces from previous strong W/SW winds at treeline and above. Surface hoar may be found buried in sheltered locations. Generally the midpack is weak at TL and above, and the entire snowpack is weak BTL. Near the divide, deeper snow-packs are a bit stronger and more supportive.
Avalanche Summary
Some small size 1 avalanches were reported on Mt. Dennis (Dennis 1 slide path) and from the Lake Louise ski area.
Confidence
Forecast snowfall amounts are uncertain on Monday
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.
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.