We are now back into classic Considerable hazard for the time being. Wind slabs, persistent slabs and cornices will be lurking around in the terrain for the next little while. Pay attention to the spike in freezing levels on Tuesday in particular.
Confidence
Moderate - Freezing levels are uncertain on Tuesday
Weather Forecast
Mainly cloudy for Monday. No precipitation expected. Temperature in the alpine -3.0 and winds will be out of the west light to moderate (30km/h). Freezing level is expected to rise to 1900 meters.
Avalanche Summary
There was a natural cycle of avalanches of up to size 3.0 on Saturday due to the strong winds and warm temperatures. Avalanches up to size 2.5 were also accidentally and remotely triggered by skiers in treeline elevations on Saturday.
Snowpack Summary
In the upper snowpack (15-20 cm down) the storm interfaces are settling out quickly and bonding. However, there is great deal of variability in the distribution of the new snow due to the strong to extreme winds on Saturday. These winds have had a profound affect on the higher elevations at treeline and in the alpine where the winds were stronger. Wind slabs will exist that have denser properties and will be more prone to initiating fractures on the Jan 6th facet interface (40-70 cm down) and thus there is still big potential for these weaknesses to spread through the snowpack causing large and destructive avalanches. This January 6th facet layer will be a fixture in the snowpack for the next few weeks at the very least so don't let this weak layer fall off your radar any time soon.
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.
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.