Lots of new snow has recently fallen. Be cautious when approaching bigger slopes as weak layers are present in the snowpack.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Another 10cm of snow has fallen during the day on Tuesday to bring our storm snow up to 35-45cm. Wednesday will bring another 10cm of snow with 30km/hr SW winds with gusts up to 50km/hr and temperatures around -7c. The weather models for Thursday show more snow with moderate winds. Cooler temperatures are expected for the weekend.
Avalanche Summary
One natural avalanche size 1.5 was observed in the Burstall Pass area. Keep in mind that human triggering is still likely.
Snowpack Summary
This recent storm has left us with 35-45cm of snow in sheltered areas and up to 90cm of storm snow in lee features. These loaded lee features are a good indication of the recent wind transport; it will be important to look for windslabs before venturing into bigger terrain. Below this storm snow are surface hoar and facet crystals which are creating a weak sliding surface for the snow to be reactive; we are calling this the December facet layer interface and it is producing easy to moderate failures in our snow tests. There is still concern for this recent storm snow to trigger the October facet layer at the bottom of the snowpack.
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.