The current windslab will likely stabilize in the next few days, but the January 6th facet layer will linger. The current snowpack is relatively complex, and deserves a fresh perspective on what is reasonable.
Weather Forecast
Mainly cloudy with isolated flurries. There may be a few cm's of accumulation from these flurries. Expect an alpine high of -6. Winds will be up to 35km/hr and from the NW. Freezing level will be around 1500m.
Avalanche Summary
Forecasters ski cut a sz1 windslab today on a 38 degree, south aspect moraine (known as Mt. Murray Moraines). The avalanche was 10-30cm thick and traveled about 50m. Traditionally, this moraine does not perform with ski cuts so it suggests that windloading is a problem right now.
Snowpack Summary
Below treeline the current snowpack consists of a thin crust on top, followed by a weak layer of facets that go to the ground. In some deeper areas the snowpack still carries well, but trail breaking is generally about 30cm deep with the odd section of wallowing. There was some new snow last night, but only a few cm's. At treeline, where the snow is deeper (115cm on average) still carries well and has some support. The melt/freeze crust goes up to 205-m. At the upper elevations, or areas that are wind prone, expect windslabs. The Jan 6th facet interface is the one to look for and it is down 20-30cm's. The alpine currently has windslabs in any lee area, as well as a persistent weak layer (Jan 6th). The depth of the Jan 6th layer varies greatly, generally 20-40cm down. So far the windslabs tend to be in immediate lees, but approach any windloaded feature with caution as there is a great deal of variability out there right now.
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.