Regions
Banff Yoho Kootenay.
Warming temperatures and moderate to strong SW winds have changed the conditions and increased the hazard to the MODERATE range for the weekend. Still generally a strong snowpack for this time of year but use caution in wind affected areas.
Weather Forecast
Isolated flurries expected for Saturday night and Sunday this week with moderate SW winds and more precipitation near the divide. The mild temperatures will continue with valley bottom high temperatures possibly reaching 8-10 degrees.
Snowpack Summary
Recent winds have created wind slabs in the alpine and a temperature crust is present on many solar aspects. The snowpack at 2000m is 50-70 cm deep. Skis travel surprisingly well, even in shallow areas. There are a couple crusts in the snowpack on south and west aspects, but on north aspects the deep snowpack is relatively strong.
Avalanche Summary
Moist snow avalanches have been observed in steep south facing terrain up to size two on Thursday. A couple wind slabs up to size 2 were also been reported in the alpine on Thursday. Sluffing in steep alpine terrain will continue until the winds calm down.
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.