Natural avalanche activity has tapered off, but skier triggered avalanches are possible. Solar aspects seem to be most reactive with large avalanches failing on an old crust. Evaluate terrain carefully and conservative decision making is recommended.
Weather Forecast
Tonight and Wednesday: A low pressure system moves inland to the South of the border. Light-moderate precipitation will begin this evening over the Southern ranges. Ridgetop winds light from the South. Alpine temperatures near -6 and freezing levels 1300 m. Thursday: Mainly cool and dry with some clouds. Ridgetop winds light from the West. Alpine temperatures near -7 and freezing levels at 1200 m. Friday: The ridge will remain over the region with dry, sunny conditions. Ridgetop winds will blow light from the West. Alpine temperatures near -9 and freezing levels at 1400 m.
Avalanche Summary
On Monday, one size 2 natural slab avalanche occurred from an East aspect. Many operators in the region did control work using explosives and triggered slab avalanches size 1-3.5 on all aspects generally above 2200 m. The large avalanches that initiated from Southerly aspects ran on a buried crust interface down 80-100 cm.
Snowpack Summary
Up to 80 cm of snow fell over the past week. The new snow added to ongoing storm snow instabilities, particularly on the west side of the region where accumulations have been highest. Buried beneath (60-100 cm) exists a surface hoar and a sun crust layer, which continue to be lingering concerns. Large looming cornices exist on ridgelines. Cornice fall could trigger a large slab avalanche on the slope below.Below treeline exists a melt-freeze crust with moist snow beneath it. The crust may be bridging instabilities deeper in the snowpack. If temperatures warm at lower elevations, you'll notice the crust breaking down and the snowpack becoming weaker.
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.