Confidence
Poor - Due to the number of field observations
Weather Forecast
Cold, clear weather looks set to continue through the weeekend.Saturday: Dry, temperatures around -25C, light NW winds.Sunday: Dry, temperatures around -25C, strong NW winds.Monday. A few flurries, maybe 1-2 cm new snow. Temperatures around -18C. Strong NW winds.
Avalanche Summary
No reports of avalanche activity.
Snowpack Summary
The limited information we have from this regions suggests treeline snowpack depths vary from 30 cm to 120 cm. Anywhere from 20 to 70 cm new snow fell with the most recent storm. Initially temperatures were relatively warm, then they cooled dramatically. As a result, the new storm snow is generally "right-side-up", meaning lower density snow sits above denser snow below. Large surface hoar crystals were buried by the recent storm snow near Elkford and likely other parts too. Strong northerly winds following the storm created wind slabs on exposed southern slopes. Recent reports suggest it is becoming more difficult to trigger these wind slabs. While this is consistent with what we commonly see when the wind subsides and temperatures dive into the -20's, the lack of observations would make me approach steep, wind loaded terrain with a lot of caution right now. At or near the base of the snowpack, I suspect you will find sugary facets, which will surely be growing with the extremely cold temperatures. The chance of triggering this layer is quite small under the current conditions, but if it was to happen, it would most likely be on a steep, convex slope with a thin snowpack.
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.