Warm temperatures and strong solar radiation may destabilize the snow today. Weak layers in the snowpack are more likely to fail as slab avalanches on slopes that are exposed to a lot of sunshine. Avoid exposure below cornices receiving direct sun.
Weather Forecast
A high pressure ridge moving up from Washington State, will bring warm temperatures and lots of sun with some cloudy periods today and tomorrow. The freezing level will be around 2000m today and 2700m tomorrow. Ridge winds southwest 10-25km/h and no snow forecast.
Snowpack Summary
Storm snow is settling, but snowpack tests still show weak layers down 20 and 50cm. Yesterday, a field team had sudden planar test results and a RB4 (Whole Block) down 80cm. On Friday whumphing was observed at tree line on a higher density layer over lighter snow. Cornices could fail from strong solar input and loose moist avalanches are likely.
Avalanche Summary
Most recent storm slab avalanches in the hwy corridor were 4 size 1.5 to 2.5 on S and N aspects. Yesterday, on steep southerly aspects, a few size 1.0, loose moist slides were observed. On Avalanche Crest yesterday, some ski touring public reported, shooting cracks, whumphing and hollow drum like sounds - OBVIOUS signs of instability!
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.