New snow is creating touchy storm slabs: It's time to rein in your terrain choices and stick to simple, no consequence terrain. Avoid all overhead hazard as well - avalanches have already been running to valley bottom.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
Significant snowfall through to Monday afternoon. SUNDAY: Periods of snow, accumulation 25-40cm by day's end / Light to moderate southeast wind / Alpine temperature -7MONDAY: Flurries, accumulation 10-20cm / Light to moderate southwest wind / Alpine temperature -12TUESDAY: Scattered flurries / Light southwest wind / Alpine temperature -10
Avalanche Summary
As of Saturday afternoon we've reached the tipping point with the new snow: Touchy storm slabs (10-40cm thick) are forming (on southeast through north aspects in the alpine) resulting in natural avalanches to Size 2. The size of natural avalanches is expected to increase and the distribution expected to be widespread by Sunday afternoon: It's time to seriously dial back the terrain use and stick to simple, no consequence terrain.
Snowpack Summary
Anywhere from 15-30cm of new, low-density snow sits on previous surfaces that may include heavily wind affected snow, surface hoar in sheltered areas and/or facets. By Saturday afternoon the new storm snow was forming slabs and running naturally on northerly aspects in the Corbin zone. Crusts can be found near the previous surface on solar aspects at high elevations and on all aspects below 1600m. The hard windslabs below the recent storm snow have not bonded well to the previous surface and are easy to trigger in isolated lee and cross-loaded features. About 70cm below the surface, you'll find sugary facet crystals which formed during December's cold snap. Although avalanches are currently unexpected at this interface, this layer could come back to life with with warming, significant loading or a large trigger at a thin spot.
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.