Ridgetop wind speeds are uncertain for Tuesday. If northerly winds are strong, new wind slabs can be expected on all aspects.
Confidence
Moderate - Wind speed and direction is uncertain on Tuesday
Weather Forecast
Tuesday: Mix of sun and cloud / Moderate north winds / Alpine temperature at -25Wednesday: Clear skies / Moderate north winds / Alpine temperature at -18Thursday: Mix of sun and cloud / Strong northwest winds / Alpine temperature at -14
Avalanche Summary
No new avalanches were reported on Sunday. I'd expect a new round of wind slab activity in response to new snow and wind on Sunday night and Monday. Northerly winds on Tuesday may promote a reverse loading pattern increasing the likelihood of wind slab activity on a variety of aspects.
Snowpack Summary
Up to 20 cm of low density snow fell on Sunday night and Monday. Moderate to strong southwest winds are expected to have shifted these fresh accumulations into wind slabs at treeline and above. Recent snow has also covered old, thicker wind and hard slabs from previous wind events. Persistent and deep persistent weakness in the mid and lower snowpack are giving variable results in snowpack tests, but are generally most touchy in shallow snowpack areas. Recent snowpack tests gave moderate but resistant results on facets and/or surface hoar buried mid-December where it was found down 45 cm, and hard but sudden collapse results on the facet/crust weakness down 116 cm near the base 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.
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.