New windslabs are quickly building with the warm temps, new snow and strong winds. Natural avalanche activity is continuing in Alpine areas.
Confidence
Good - Intensity of incoming weather systems is uncertain
Weather Forecast
Another 5-6cm of storm snow will likely fall over the next 24hrs with moderate to strong SW winds at higher elevations. Temperatures are forecast to be -5C ish at the higher elevations so expect new windslabs to build quickly over the next 24hrs.
Avalanche Summary
Visibility was limited throuhgout the day on Sunday but there were a few new sz 2 avalanches observed in Alpine terrain.
Snowpack Summary
Up to 20cm of new snow had fallen by the end of the day under the influence of moderate to strong SW winds at treeline and above. New storm slabs are building in open areas on mainly N and E aspects that will be sensitive to human triggerring. The 0211 layer is now down roughly 80-100cm and continues to produces sheers that range from easy to moderate to hard. The unpredictable nature of this layer makes it tough to evaluate and requires constant monitoring as you move through the terrain.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.