Regions
Banff Yoho Kootenay.
Avalanche control planned for Sunshine tonight, Bosworth, and Mt. Stephen on Wednesday. Depending on results we may also do Simpson, Whymper, and clean up on Sunshine. Please no recreational activities in these areas on Wednesday.
Weather Forecast
The cold front passes by midnight: the snow should end, temperatures continue to drop, and winds should taper. For Wednesday, expect isolated flurries and light winds from the W gusting to 50 km/hr. Stable weather is forecasted for the remainder of the week with 2 nights of -18C temperatures (Thur & Fri) and warmer for the weekend (-12C).
Snowpack Summary
Essentially 2 major snowfall events in the past week has created the snowpack. The midpack is supportive, but not glued to the ground very well with two column test failures at the ground level on Monday. A layer of surface hoar exists 15-20 cm off the ground, but no test results were found on this layer.
Avalanche Summary
Visibility has been poor today, but some avalanches were heard. Today ski cutting around Sunshine produced only small surface avalanches with nothing stepping down. This may change with more load overnight from snow and wind. We expect natural avalanche activity to continue tomorrow with moderate W winds adding load to the weak layers.
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.
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.