Forecast snow amounts are uncertain. If snow amounts at treeline exceed 20cm, the danger will likely be high there too.
Confidence
Poor - Forecast snowfall amounts are uncertain
Weather Forecast
Synopsis: A broad upper level trough settles in over the Southern Coast which should generate significant precipitation through the weekend. Precipitation amounts have varied wildly from run to run. The amounts shown below are my best guess, but I won't be surprised if the region receives more.Saturday: Freezing Level: 600m rising to 1300 - 1500m Precipitation: 5 -15mm | 5 - 20cm; Treeline Wind: Light, South | Ridgetop Wind: Strong, SouthSunday: Freezing Level: 500m rising to 1200 - 1500m Precipitation: 2-5mm | 2-10cm; Treeline Wind: Moderate, SW | Ridgetop Wind: Strong, SWMonday: Freezing Level: 400m rising to 1400 - 1800m; Precipitation: Trace; Treeline Wind: Light, SE | Ridgetop Wind: Light, SE
Avalanche Summary
No new reports of avalanches.
Snowpack Summary
The recent snow is expected to settle and bond to the mix of old surface crusts and wind slabs with daytime warming and overnight freezing levels dropping down to near valley bottoms. The forecast new snow and strong Southwest winds are expected to develop new storm slabs over the next few days that may release down to the old surface of melt-freeze crusts and/or where facets are sitting on old wind slabs. The added load of storm snow or storm slab avalanches in motion may trigger the March persistent weak layer. The early-March crust/facet layer is down about 100-150 cm and the early February layer is now down close to 200 cm.
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.