Regions
Banff Yoho Kootenay.
While conditions are generally good, there are still some terrain features that warrant caution or avoidance. Mainly steep southerly aspects in the alpine. Additionally, it is the time of year to start early and finish early to beat daytime heating.
Weather Forecast
Cool temps will remain tomorrow, -1 in the valley and -10 at ridge level. Cloud is expected to return with light accumulations of snow, up to 5cm. The wind is expected to increase to up to 50km an hour at ridge elevation, from the SW.
Snowpack Summary
20-30 cm of recent snow has formed a variable soft slab on some features that is slowly bonding to the underlying surfaces, such as melt freeze crust on solar aspects and older snow layers including facets on shady aspects. Below this the majority of the snowpack is stable and has recently shown no results in tests.
Avalanche Summary
A size 1 avalanche was observed in Unity Bowl near the Lake Louise Ski area today. It was located on a NE aspect at 2500m. Also, yesterday there was a skier accidental size 2.5 on Observation Sub Peak. A group of 3 were descending a steep rocky South aspect when 1 skier triggered the slide and went for a long ride. The party self evacuated.
Confidence
Freezing levels are uncertain on Thursday
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.
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.