Regions
Banff Yoho Kootenay.
The recent snow has created small reactive windslabs in the alpine and ideal conditions for loose snow avalanches. The main concern is in areas with significant terrain traps. Ice climbers in particular should be weary of this problem.
Weather Forecast
Another pulse is expected this evening with forecasted amount of snow averaging 4-8cm, As this moves through winds are expected to remains moderate in the alpine and then trending to light by tomorrow. Another arctic flow is approaching, by Tuesday temperatures will sink to the low -20's with beautiful clear sky's.
Snowpack Summary
10-15cm of new snow last night sits on a faceted snowpack. In the alpine the new snow has had some wind affect with small slabs developing in lees, this new slab sits on hard wind affected snow from the past week. At treeline and below the new snow remains low density and overlays a heavily faceted snowpack with little structure or support.
Avalanche Summary
Loose dry avalanches were observed in steep terrain, releasing from last nights storm snow. The southern part of the forecast region appeared to have slightly more snow and wind, Sunshine ski patrol reported numerus size 1 avalanches in areas where new wind slab exist. These avalanches were triggered by explosives and ski cuts.
Problems
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.
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.