Regions
Banff Yoho Kootenay.
Warm temperatures in the valley bottoms near Banff have not made it up into the Continental Divide area, and the snowpack has remains solid. Windslabs appear to be building in high elevation areas, and climbers should avoid south facing gullies.
Weather Forecast
Westerly flow continues with a gradual falling of freezing levels over the main ranges on Thursday. 0-5 cm of snow is expected overnight on Wed, and by Thursday we expect cloud cover and strong alpine winds to keep the higher elevations cool. Valley bottom temperatures will reach +9 in Banff on Thursday.
Snowpack Summary
There is a wide range of conditions from east to west at this time. Eastern areas (Banff) are subject to the warm temperatures which are effecting the snowpack on S and W aspects. Further east the temperatures have remained cool enough that treeline and alpine snowpacks have remained solid. We expect this pattern to continue for several more days.
Avalanche Summary
Another report of a small windslab triggered by skiers on Mt. Cathedral two days ago. This makes for several small windslabs being triggered in isolated areas this week, which is not a huge trend but certainty notable.
Problems
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.