A natural avalanche cycle continues this morning with moderate to strong Southerly winds moving storm snow and overloading weak layers. Many avalanches are running to valley bottom.
Weather Forecast
Cloudy with sunny periods, light precipitation, moderate SW winds and alpine high of -9C. A lull in the weather Wednesday then Thursday another storm front is forecast to hit bringing heavy precipitation into the weekend.
Snowpack Summary
60cm of storm snow in the last 4 days, 35cm in the last 24hrs at 1900m, accompanied by moderate to strong S'ly winds. Expect to find wind slab along ridge lines and lee features due to the moderate south winds in the Alpine. The Jan 16 surface hoar is down ~70cm, Jan 4 down ~90cm and Dec 15 down ~1m+ making for a complex sandwich of weak layers.
Avalanche Summary
We are experiencing a widespread natural avalanche cycle with slides to size 3.5. Avalanches have been running to full path to the bottom of runnout. Initially the cycle began with light winds, warmer temps and heavy precipitation. Now the S'ly winds have picked up continuing the overloading of the weak layers in the snowpack.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Thursday
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.
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.