Stability will deteriorate over the day as new snow stacks up. There's a good chance this dump will be enough to bring our buried weak layer back to life. Consider the danger to be HIGH in areas that receive over 30 cm of new snow.
Weather Forecast
Thursday night: Cloudy with continuing flurries bringing 10-15 cm of new snow. Moderate to strong southwest winds.Friday: Cloudy with continuing flurries bringing around 10 cm of new snow and new snow totals to 25-30 cm. Snowfall continuing overnight. Light to moderate southwest winds. Alpine high temperatures around -6.Saturday: Mainly cloudy with easing flurries bringing up to 5 cm of new snow and new snow totals to 40-50 cm. Light winds shifting from southwest to northeast. Alpine high temperatures around -12 and falling over the day.Sunday: Mainly cloudy with isolated flurries and a trace of new snow. Light northeast winds. Alpine high temperatures around -26.
Avalanche Summary
Reports from the region on Wednesday included one observation of a small remote (from a skier at a distance) triggered wind slab occurring in the lee of ridgecrest on a north aspect at 1850 metres. On Tuesday reported avalanche activity was limited to a size 2 cornice failure above a southeast facing slope at 2500 m. No new avalanche activity reported on Monday. On Sunday cornice failures to size 1.5 were observed on north through east facing terrain around 2000 m. Small natural wind slab avalanches to size 1 were reported on east and northeast facing terrain between 2000 and 2300 m.On Saturday a skier triggered a small persistent slab avalanche on an east facing feature at 2000 m, failing on the mid-January surface hoar.
Snowpack Summary
New snow has begun to bury the previous surface, which consists mainly of wind-affected surfaces at higher elevations with a new layer of surface hoar present at lower elevations and in some protected areas closer to treeline. Sun crust is being buried on steep, south-facing aspects. Areas where sun crust and surface hoar coexist could produce particularly touchy slabs as new snow accumulates. 15 to 45 cm of older storm snow continues to consolidate above the mid-January persistent weak layer (PWL). This PWL is made up of large surface hoar that is most prevalent at and below treeline, with enhanced reactivity noted between 1500 and 1800 m. On steep solar aspects this interface presents as a crust, there may be locations where the surface hoar actually sits on the crust. Potential exists for this layer to become increasingly reactive as new snow adds load to the snowpack. Slab releases or loose snow avalanches formed of new snow may also act as a trigger for this layer.The middle and lower portions of the snowpack are generally well-settled and strong.
Problems
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.
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.