If the storm Friday night drops 25 cm or more new snow, consider all elevations to be at high danger.
Confidence
Fair - Intensity of incoming weather is uncertain
Weather Forecast
Friday night: 10-15 cm new snow with strong to extreme SW ridgetop winds.Saturday: Approximately 10 cm new snow with strong winds veering westerly. Freezing level staying at valley bottom in most areas.Sunday: Another winter storm bringing around 10-15 cm additional snow late in the day and strong winds. Freezing levels remaining at valley bottom.Monday: Further snowfall likely, with heavy pulses possible in localized areas. Strong SW winds. Freezing levels remaining at valley bottom.
Avalanche Summary
Loose snow activity was observed on Thursday. Observations on Friday were limited to Treeline and below and there were no reports of slab avalanches. If new snow amounts exceed 25 cm by Saturday, I anticipate a significant avalanche cycle will occur in this region.
Snowpack Summary
Dense new snow is setting up a fresh storm slab on top of the previous cold, low density snow from the last few days. This cold, low density snow will very likely act as a weak layer, enhancing the potential for slab avalanches to run. A rain crust lies buried around 45cm below the surface up to around 1900 m. The bond at this crust is reported to be quite good. However, on steep slopes, this interface could still act as a good sliding surface. Weak layers lower in the snowpack have generally ceased to be of concern, except perhaps in thin rocky areas.
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.
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.