Avalanche control today. All permit areas are closed. A perfect opportunity to go to the local ski hills!
Weather Forecast
Today, periods of snow (17cm) accompanied by moderate to extreme S'ly winds and freezing level expecting to rise to 1500m. Another 9cm forecast for tonight with winds shifting to moderate SW gusting to extreme. A cooling trend with light precipitation is expected for the weekend.
Snowpack Summary
30cm+ in past 48hrs, warm temp's, and moderate to strong winds are building reactive storm slabs. The Dec 9 surface hoar/facet/crust persistent weak layer is buried 90cm+ and is producing large whumphs and sudden planar results. The Nov 21 surface hoar/facet persistent weak layer is down ~140cm.
Avalanche Summary
10 avalanches recorded in the highway corridor east of Rogers Pass summit in the last 24hrs. Notably, three of these slides were size 3.5.
Confidence
Intensity of incoming weather systems is uncertain
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.