Our early season snowpack is complex, with surface hoar layers, crusts, and pockets of basal facets. It was also just hammered with a dump of snow. Remember that it needs time to adjust to the new load as the sun lures you over the next few days.
Weather Forecast
An arctic high is moving over us, bringing dry cold weather. We may see a few flurries today and winds should shift to the NW at ridgetop and may reverse load slopes. Friday looks clear and cold, expect temps to drop to the low teens. Saturday we may see a mild inversion as temps start to rise back to around -5'C.
Snowpack Summary
~1m of storm snow is settling into a slab. Strong S-SW winds at treeline and above continue to load lee features, forming deep loaded pockets. Surface hoar layers down ~1m (Nov11) and 1.5m (Nov5) are still a concern. Weak facetted snow exists on high elevation N/NE aspects.
Avalanche Summary
Yesterday, there were several size 2-2.5 slab avalanches, likely triggered by wind-loading. Good visibility after the avalanche cycle from earlier this week showed that many avalanches were propagating widely, likely on the Nov 11 surface hoar. Some were also stepping down to deeper layers, including the Nov 5 surface hoar and the basal facets.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.