Regions
Northwest Inland.
Moderate winds are expected to form touchy fresh wind slabs in exposed terrain on Sunday.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
SUNDAY: partly cloudy with flurries starting in the afternoon, up to 5cm expected overnight, moderate southwesterly winds, freezing level of 1000m. MONDAY: lingering flurries with sunny breaks, moderate northwest winds, freezing level of 1000m. TUESDAY: mainly sunny, light south east winds, freezing level of 800m.
Avalanche Summary
No new avalanches have been reported recently although I suspect wind slabs are still touchy. If the sun comes out, natural avalanches are possible on steep south facing terrain features. In the far north, deeply buried persistent weak layers may still be reactive to large triggers such as a small avalanche stepping down or a cornice failure.
Snowpack Summary
Settling storm snow overlies a melt freeze crust buried on February 12th that extends up to around 2000m elevation. The upper snowpack is reported to be bonding well to this crust. Moist snow can be found at lower elevations and on solar aspects. Recent wind has redistributed the surface snow at higher elevations forming wind slabs in lee features. The early January surface hoar/facet layer is down around 1 meter and remains a concern. This layer seems the most reactive in the north of the region but may still be a problem in the south as well. Shallow snowpack areas in the east and north of the region have a weak base layer of facetted snow on or just above the ground.
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.