Avalanche conditions could vary dramatically between aspects and elevations Decision making may be more tricky than the Moderate danger rating implies.
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Saturday
Weather Forecast
SATURDAY: Mainly cloudy with continued light snowfall bringing another 1-3cm of accumulation. Freezing levels around 1300m and winds are expected to be light from the southwest. SUNDAY: Another 5-10cm possible overnight before continued light snowfall brings1-3cm of accumulation throughout the day. Freezing levels rising throughout the day to as high as 1500m and winds are expected to be light from the southwest. MONDAY: Moderate rain/snow with freeing levels around 1800m.
Avalanche Summary
Reports from Wednesday include limited results with explosives control producing only one Size 2.5 persistent slab avalanche releasing on the early-January surface hoar down 100cm in a lower elevation start zone where previous surface hoar growth was prevalent. Reports from Thursday include more evidence of recent persistent slab avalanche activity running on the early January surface hoar, with a two-day old 60cm deep Size 2.5 observed on a south facing alpine slope.
Snowpack Summary
A supportive near surface crust is likely in most places aside from shaded aspects at treeline elevations, and lower elevations that are under melt-freeze conditions. This crust and perhaps new surface hoar (where it survived the heat, rain and sun) could be buried by as much as 15-20cm of fresh snow or deeper wind slabs. Avalanche professionals are still monitoring the persistent weakness buried early January, which is now down 80-120 cm. In most places it is no longer sensitive to light triggers. However, in specific locations it still produces hard, but sudden results in snowpack tests.
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.