Up to 25cm of new snow Monday, with an additional 30+cm on Tuesday. Winds will remain strong from the SW. If this weather forecast comes true, a large natural avalanche cycle is expected to occur. It is time for very conservative terrain selection!
Confidence
Fair - Timing of incoming weather is uncertain
Weather Forecast
Another 25cm or more possible on monday with an additional 30cm+ on Tuesday. Strong to extreme winds from the SW will continue.
Avalanche Summary
Limited observations due to variable visibility, but did see a few skier triggered slabs up to size 1.0 that were 30cm thick on average.
Snowpack Summary
15 to 20cm of new snow overnight forming soft and hard wind slabs in alpine and treeline locations, especially on N and E aspects. Moderate shears exist down 17cm and 23cm. Three separate crusts layers make up the midpack, with moderate to hard test results failing below these different crusts. Total height of snow at 2200m was 70cm.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.