Regions
Northwest Inland.
There's fresh snow and clearing skies in store for the weekend which sounds amazing, but we need to SLOW IT WAY DOWN and stick to conservative terrain as the snowpack adjusts to the recent load.
Confidence
Poor - Due to the number of field observations
Weather Forecast
Snowfall should slowly taper overnight. I'm expecting 5 to 20cm out of this last push. Winds should ease back (slightly), but I'm still expecting strong SW winds in the alpine Saturday. No snowfall is expected on Saturday, Sunday or Monday. Looks like it goes clear and dry through at least Tuesday.
Avalanche Summary
With the intense storm obscuring views, observations have been limited. I expect there is a widespread natural avalanche cycle occurring, we'll probably learn more about it as skies clear this weekend.
Snowpack Summary
The storm has produced approximately 20 to 50 cm of new snow accompanied by strong to extreme winds out of the E through SE. There are a number of weak layers in our snowpack, this storm should be a good test for all of them. In places the new storm snow sits on the early February surface hoar, little is known about the distribution of this interface. The late January crust is probably down 60 to 100cm in the south, it's likely shallower in the north. The mid-January rain crust(with some spatially spotty surface hoar on top) is down over a meter. It might still be a problem in thin snowpack areas. The crust/facet combination from November can be found near the ground. It's not an easy snowpack to work with, we'd greatly appreciate your observations via the Mountain Information Network.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.