Diligence may be required to maintain conservative decisions when seeking decent riding conditions over the weekend.
Weather Forecast
The forecast period is looking mostly cloudy with a chance of light flurries especially on Saturday. Freezing levels remaining in valley bottoms for the forecast period, with no more warm air expected at higher elevations. Winds should remain generally light and variable.
Avalanche Summary
Reports from Thursday include several explosive triggered storm slab and persistent slab avalanches up to Size 3, some stepping down to deeper persistent weak layers near the ground.
Snowpack Summary
There is a great deal of variability across the region. The West and South have received up to 60 cm of storm snow earlier in the week, quickly followed by high freezing levels and warm air up into the alpine which has resulted in a breakable surface crust. The North and East of the region have had 20-30 cm of cold dry new snow which has since been redistributed into touchy soft wind slabs, while large surface hoar is growing in sheltered areas. Deeper in the snowpack there is a persistent weak layer of surface hoar and crust that is now down about 30-80 cm. Recent snowpack tests on the West side of the range produced easy resistant results down 25 cm in the recent storm snow, and moderate to hard but sudden results down 80-90 cm on buried surface hoar sitting on a crust.
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.