Steep south aspects had moist snow today. With temps on the rise, expect south aspects to be tricky skiing. If good turns are on order, staying low and looking for sheltered areas will be your best bet.
Weather Forecast
The big story is going to be the winds. They are expected to pick up tonight and peak tomorrow morning. 3000m winds will hit 155km/hr!! 2500m will be less at only 80km/hr! Looks like snow for Winnipeg. Other than the ridiculous winds, they day will be quite nice. Above zero at all elevations, and mostly clear skies.
Avalanche Summary
Forecasters witnessed one slab avalanche today that was triggered by sluffing in steep, unsupported cliff terrain. The avalanche eventually included all the trouble layers, including pulling out pockets on the Nov 6th crust. It was a size 2, NW asp, 40 degree plus terrain. Mt Buller was the area.
Snowpack Summary
A very windy day today. Even valley bottom saw some snow transport. The alpine is currently being raked by extreme winds. Cornices, sluffing and windslabs can all be expected from this wind event. The transition to alpine terrain was very distinct in terms of windloading. Open areas at treeline were instantly "slabby". These slabs extended well below ridgelines. On south aspects, various problem layers are becoming difficult to inspect/locate within the treeline snowpack. Generally it felt reasonably well settled with a weak base. No surprises. On other aspects, the snowpack is more obvious. The Dec crust is down 20-40 depending on wind orientation. Below treeline, the winds have had a slight effect on the snow surface but no real avalanche problems are there yet. Valley bottom snow depth is 70cm's, treeline is 90-100cm's and alpine is variable.
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.
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.