This forecast is based on very few field observations and a high level of uncertainty exists. A conservative approach to terrain selection is critical until more snowpack data becomes available.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Friday: 5-10cm of new snow / Strong southwest winds / Freezing level at 900mSaturday: Light flurries / Light and variable winds / Freezing level at 400mSunday: Mix of sun and cloud / Light and variable winds / Freezing level at valley bottom with alpine temperatures dropping to about -13
Avalanche Summary
No new avalanches were reported in this region. This may speak to a lack of observations rather than actual conditions. With recent wind and snowfall, a natural storm slab avalanche cycle is expected to have occurred on Thursday. Human triggering of these storm slabs is expected to continue into the weekend.We currently have very limited observations from this region. Please submit your observations to the Mountain Information Network (MIN).
Snowpack Summary
Up to 40cm of new snow has fallen in the past few days. At higher elevations, southerly winds (gusting strong at times) likely redistributed the new snow, forming wind slabs on lee features.Below the recent storm snow you may find a couple of crusts which formed as a result of last week's rain. That said, little is known about the reactivity of these crusts or the elevation bands at which you're likely to find them. A major feature in the snowpack is a crust which formed around November 11th and can be found approximately 100cm down at treeline elevations. We currently have very limited snowpack observations within this region and it is critical to supplement this information with your own observations.The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 200+cm in the alpine, 100-160cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks.
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.