Confidence
Poor - Due to limited field observations for the entire period
Weather Forecast
A deep low pressure system off the Gulf of Alaska will continue to bring moist, warm and an active weather pattern over the next few days. Weaker impulses embedded in the flow will bring moderate amounts of precipitation over the mountains. Timing of these pulses are tricky to predict. Friday: FLVL’s 1400 m, snow amounts 10-20 cm, ridgetop winds SE 40- gusting 60 km/hr, alpine temps -3.0.Saturday: FLVL’s 1200m, snow amounts up to 15 cm, ridgetop winds SE 40-50 km/hr, alpine temps -4.0. Sunday: FLVL’s 1000-1200 m, snow amounts 5-8 cm, ridgetop winds S 10 km/hr, alpine temps -4.0.
Avalanche Summary
No new avalanche observations have been reported. Natural avalanche activity will likely pick up again with forecast wind and snow.
Snowpack Summary
The region will continue to see pulses of moderate snow accumulations, and strong ridgetop winds. Storm slabs and new wind slabs will load a variety of weak surfaces. These surfaces consist of large surface hoar, a thin sun crust, surface facets, moist snow, or preserved storm snow depending on elevation, sun and wind exposure, slope angle, time of day, and aspect. The new snow may have a poor bond to these underlying weaknesses. Snowpack tests continue to show sudden collapse (or "drops") results on the early November facet/crust deep persistent weakness, but because this weakness is so close to the ground in most areas, associated avalanche activity will likely be limited to slopes with smooth ground cover (e.g. scree slopes, rock slabs, summer firn, glaciers, etc.).
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.