Wide variability in the sensitivity of the storm slab over the Dec 20 layer through the forecast area, be cautious out there.
Weather Forecast
Expecting seasonally cold temps and broken skies over the day Sunday. If the sun comes out for extended periods be aware of the possibility of increasing hazard on solar slopes and especially from rocky shallow areas in the sun. So, if you find yourself on a nice steep sunny slope slapping on sunscreen and having lunch, might be best to move on!
Snowpack Summary
Overall, field teams are finding a weak snowpack. The Dec 20 facet/surface hoar layer is out there. It was proving to be very sensitive to fluctuations in temp and solar radiation and showed exceptional propagating properties for having only a weak soft storm slab over it.
Avalanche Summary
A natural avalanche cycle up to sz 3 on south to westerly (solar) aspects occurred over the week. A dramatic temperature inversion at around 2500ms (cold air low/warm above) was actively affecting the slopes.
Confidence
Due to the number of field observations
Problems
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.
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.