All the recent avalanche activity should serve as a flashing red light, a conservative and cautious approach is required in the mountains this weekend.
Confidence
Fair - Due to variable snowpack conditions
Weather Forecast
Friday: Light Winds out of North. Freezing level at valley bottom. No snow. 1500m temp: -10Saturday: Carbon copy of Friday. Clear skies, no snow and light NW winds. 1500m temp: -10Sunday: High pressure drives a fairly boring weather pattern. Same as Saturday.
Avalanche Summary
On Monday avalanches released naturally and were initiated by sledders, skiers and explosives. Avalanche activity was widespread to size 3. It should be noted that there was some remote triggering too.
Snowpack Summary
The recent storm has brought 60 - 100cm of new snow to the region. Consistent southwesterly winds have redistributed the new snow (dramatically in some areas) to create widespread windslabbing on lee and open features in the alpine and exposed treeline. Where the wind has been strongest, we have reports of windslabs much lower on slopes than normal.There have been avalanches reported both within the storm layers as well as at the initial storm interface, the January 4th layer. This layer consists of small facets, surface hoar on sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. The bonds with the facetted snow are improving while the surface hoar / sun crust interface is weak. The midpack is well bonded and strong. The deep crust/facet combo from early November still exists and concern remains (although unlikely) for triggering this layer from a shallow spot.
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.
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.