Buried old wind slabs (persistent slab) vary in reactivity and warrant a site by site assessment.
Weather Forecast
An arctic front has pushed the jet stream to our south. Cold air and L winds will persist through Thursday.Thursdays forecast is for a mix of sun and cloud, alpine lows -18C, highs -14 C, and light wind. A ridge sliding in from the Coast will give warming temps and light W winds in to the weekend.
Snowpack Summary
Up to 15cm of snow (3 days), sits on pockets of old wind slab in exposed areas (these sit on weak facets and srfce hoar many locations), and a facetted upper snowpack in sheltered areas at all elevations. A strong mid snowpack crust is providing some strength around treeline. The faceting process (weakening) is well underway in the lower snowpack.
Avalanche Summary
No new avalanches observed or reported.
Confidence
Due to the number of field observations
Problems
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.