High winds arrived on Friday & Saturday, but brought only a little new snow. Watch for avalanche hazard to increase rapidly with sustained above-freezing temperatures early next week.
Weather Forecast
Cloudy on Saturday with continued strong-extreme Westerly winds. These remain strong Sunday, easing to light through Monday. Sunday & Monday look mainly clear. Temperatures fall this afternoon, then rise slowly through Sunday, approaching zero late evening. By Monday, many forecast models predict temperatures well above freezing at most elevations.
Snowpack Summary
5-10cm of recent snow in higher terrain has formed Wind Slabs, which may be found in usually sheltered locations, due to extreme W winds Friday night. Buried below are older wind slabs, more difficult to trigger. Down 50 cm is a weak layer in isolated areas, and 1m deep is a faceting rain crust. Sensitivity of these will rise with temperatures.
Avalanche Summary
Several small Wind Slab avalanches were observed on Saturday.
Confidence
Freezing levels are uncertain
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.