The basal facet problem has been the sliding layer for the last two natural avalanches. This problem will be with us for a long time. Stay disciplined.
Weather Forecast
Tuesday and Wednesday are forecast to bring a mix of sun and cloud along with light SW winds and alpine temps around -7c.We have had a temperature inversion(cold in the valley bottom and warm up high) for the last couple of days and we might see this again for Tuesday. Light flurries are expected for Thursday.
Avalanche Summary
One natural size 2 slab avalanche occurred sometime during Sunday night in a west facing gully off of Mt. Buller. The failure plane was mostly on the basal facets and scrubbed to ground.
Snowpack Summary
Wind slabs are pretty much everywhere in the alpine and open areas at tree line. The upper half of the snowpack is well settled and comprised of two hard layers, each around 35cm thick. The upper hard layer is still producing moderate test results on what appears to be the December 30 facets. The lower hard layer is resting on the Dec 10 facets(start of the basal facets) which is approximately 70cm down. The basal facets make up the bottom 50-60cm of the snow pack. We had several repeatable compression tests(sudden planar) in the moderate to hard range that occurred on the basal facets.Have a look on our Facebook page for our latest video showing the compression test on the basal facets: https://www.facebook.com/KCPublicSafety/
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.