Take the time to carefully evaluate newly accessed terrain, large avalanches have been widespread over most aspects and elevations this week over the entire forecast area.
Weather Forecast
The edge of a series of troughs from the Aleutian Pacific region are being brought SE'ward through the forecast zone but are being kept mostly at bay by cold arctic air. Flurries are expected overnight but should result in less than 10cm of new snow. Clearing expected by the end of the weekend and into next week with sunshine and cold nights.
Snowpack Summary
The past week's storm snow has been redistributed by strong, variable direction winds. Where snow remains, new wind slabs overlie a settled upper snowpack which is sitting on the persistent weak layers in the mid snowpack. Widespread avalanche activity on these weak layers followed last week's storm, slopes without recent avalanches are suspect.
Avalanche Summary
Isolated windslab avalanches (likely failing on a persistent mid snowpack weakness, and up to size 2.5) were observed today in the Tonquin valley. East, South, and North aspects have formed windslabs and large cornices that have failed in the last 24 hrs in the north portion of the forecast zone.
Confidence
Due to the number of field observations
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.
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.