Avalanche danger will vary from place to place depending on local snowfall amounts and freezing levels. The heaviest precipitation is expected in the west.
Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period
Weather Forecast
Tuesday night/ Wednesday: 30-50 cm snow. Strong to extreme W winds. Freezing level around 1500 m overnight, rising to about 2000 m in the south (~1700 m in the north) on Wednesday.Thursday: Light snow. Moderate to strong NW winds. Freezing level around 1600 m. Friday: Light snow. Light S winds. Freezing level around 1500 m.
Avalanche Summary
Most of the recent avalanche activity has been on high elevation north aspects. A cycle of natural slabs to size 3 which occurred during last weekend’s storm petered to a few size 2s by Monday. A few skier-remote triggered slabs were also reported on Sunday. These either failed on a storm snow weakness, or on surface hoar buried below the storm snow. Below about 2300 m, skiers were triggering loose wet avalanches on steep terrain. Another natural avalanche cycle is expected in response to Wednesday's storm.
Snowpack Summary
40-70 cm recent storm snow is sitting on a variable interface, consisting of a crust, moist snow, surface hoar or facets. The surface hoar or facet interface is mainly found on high-elevation northerly aspects. It has been very touchy, with remote skier-triggering occurring. Forecast precipitation will add to this storm slab problem and create new wind slabs at high elevations, and weaken the snowpack with rain at low elevations. Large cornices are likely to increase in size and become more prone to failure during Wednesday’s storm.
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.
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.