Touchy thin new wind slabs may develop exposed lee terrain on Wednesday if we see more snowfall and/or wind than forecast. If so, watch your exposure to terrain traps below.
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
Wednesday: Mainly cloudy with periods of light snow around 5 cm in the north and 10 cm in the south. The freezing level is at valley bottom. Winds are light to moderate from the W-NW. Thursday: Mainly cloudy with a chance of flurries. Temperatures should cool a few degrees to around -10 at treeline. Winds are light from the north. Friday: Mainly sunny. Treeline temperatures are around -12 during the day and -20 overnight.
Avalanche Summary
With the cooler temperatures and increased cloud cover on Sunday, natural avalanche activity appears to have mostly stopped. No new avalanches have been reported.
Snowpack Summary
The recent dry, warm weather has generally consolidated the upper snowpack. As temperatures now begin to cool, stability in the upper snowpack should increase further. Keep in mind that 'Low Hazard' does not mean 'No Hazard' and that residual risk of avalanches still exists. Old, stubborn wind slabs may still exist in isolated areas. A basal facet/crust combo (weak sugary snow above and below a crust) near the ground is still a concern in some areas. The depth of this layer makes triggering an avalanche on it unlikely (maybe a heavy load on a thin spot in steep terrain, rapid temperature change, or cornice fall), but the consequences would be large and very destructive.Widespread large surface hoar was reported throughout the region. This layer is now probably buried by a few centimetres of snow. In some places the surface hoar may have been sitting on a crust, it may have only been a sun crust, and it may even have included sugary faceted snow. At any rate, it looks like this layer will be one to keep a close eye on in the coming weeks.
Problems
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.