Avoid steep sunny slopes, and exercise careful route-finding if you transition into Alpine terrain - Deep Persistent slabs are very hard to predict or assess, and the consequences of triggering such a deep avalanche would be nasty.
Weather Forecast
Sunday: Mainly sunny. Moderate Westerly winds. Freezing level at Valley Floor. Treeline Low -10, High -7.5Monday: Sunny. Light Easterly winds. Freezing Level 1400m. Treeline Low -10, High -6Tuesday: Increasing cloud. Flurries developing. Light-Moderate Southerly winds. Freezing Level rising to Treeline. Treeline Low -6, High 1.
Snowpack Summary
Around 30-40mm of rain on Saturday (less in the Eastern ranges) has saturated an already warm snowpack. A surface refreeze is expected by Friday morning. Strong SW winds are blowing new snowfall into Storm Slabs above 2100m. Deep Persistent layers will more sensitive than usual due to recent warmth, and the added weight of the new rain/snow.
Avalanche Summary
Several small Loose Wet avalanches and one Large (Size 2) Wet slab were observed Below Treeline on Saturday. It is expected more natural activity will be apparent on Sunday with better visibility.Three Large (Size 3) Deep Persistent slabs were observed during the past week (Most recent: Wednesday night), running from the Alpine to Valley Floor.
Confidence
Due to the number and quality of field observations
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.
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.