Snowfall amounts vary across the region. The hazard may change dependent on the amount of new snow. More snow than forecast may push the hazard rating higher than forecast.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
We're in the path of a series of Pacific weather systems that will bring snow at higher elevations, and rain mixed with snow at valley bottoms. Southern portions of the forecast area may see higher than forecast temperatures.Thursday night: Freezing level: at valley bottom; A minor clearing will occur late tonight before the next storm system. Winds from the south west and moderate to strong at ridge top.Friday: Freezing level: 1000m; Yet another wave will bring more snow (10 to 20 cm) to the region, with continued moderate to strong south west winds at ridge top.Saturday: Freezing level around 900m; A bit of a break in the weather on Saturday. Flurries with a trace of precipitation ( perhaps 5 cm ), light to moderate winds at ridge top from the south west.Sunday: Freezing level at 800m; More snow as another wave moves into the interior. 10 to 15 cm new snow possible. Winds from the south west, moderate gusting to strong at ridge tops.
Avalanche Summary
Reports of numerous size 1 to 12 skier controlled and natural avalanches up to size 2.5 in the past 24 hrs. We expect the number of reported avalanches to increase with the snow loading and strong upper elevation winds.
Snowpack Summary
Some parts of the Purcells have received up to 80cm of storm snow in the past 48 hrs. on a variety of weak surfaces(surface hoar, facets, sun crust) These weak layers will be problematic for the near future and it will take time for the new snow to bond with the old surfaces. Significant weak layers of large surface hoar and facetted snow are now buried 80 to 100cm below the new snow surface. These weak layers are expected to remain a problem for the foreseeable future. The rest of the snowpack is generally well consolidated. Forecast strong winds at ridge tops will redistribute the new snow and form wind slabs on lee slopes. A facet/crust weakness near the bottom of the snowpack has gone dormant for the most part. The depth of this layer makes triggering an avalanche unlikely but the consequences would be very serious.
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.