Regions
South Coast Inland.
Watch for signs wind transport in exposed terrain. Moderate to strong winds and light snowfall on Sunday may form new wind slabs.
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Sunday
Weather Forecast
5-10 cm of new snow is forecast between Saturday evening and Sunday afternoon. Freezing levels are expected to reach around 1200 m and alpine wind is forecast to be moderate to strong from the southwest. 10-20 cm of new snowfall forecast between Sunday evening and Monday afternoon. Freezing levels are forecast to reach around 1400 m in the afternoon and alpine wind is forecast to remain moderate to strong from the southwest. Another 5 cm of snow is currently forecast for Tuesday with afternoon freezing levels 1000 m and light to moderate alpine wind.
Avalanche Summary
No new avalanches were observed on Friday. On Thursday, explosive control in the Duffey triggered several size 2-2.5 slabs with 30-50 cm thick crowns, noted for pulling into low angle terrain above the start zones. Widespread natural activity was reported on Wednesday and early Thursday during the warm storm system. Many of these avalanches were wet and gouged all the way to ground in confined paths.
Snowpack Summary
In the Duffey above around 1800 m elevation, 20 cm of heavy powder overlies the widespread mid-February crust layer. Wind slabs and cornices are being reported in north facing alpine terrain. Below around 1800 m, the surface crust is reported to be supportive to the weight of a skier. Two surface hoar layers down 100 cm and 150 cm are still reactive in snowpack tests but would be very difficult to trigger without something heavy like a cornice fall or smaller avalanche stepping down.
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.