The next major storm is expected to start Wednesday night. If you're sick of seeing red, read the forecaster blog.
Confidence
Fair - Track of incoming weather is uncertain on Saturday
Weather Forecast
Thursday: moderate to heavy snowfall starting Wednesday evening and continuing through Thursday night - strong southwest winds - freezing level @ 1300m Friday: light snowfall - moderate southwest winds - freezing level @ 800m Saturday: light snowfall - light and variable winds - freezing level @ 1200m
Avalanche Summary
Recent avalanche observations have been fairly limited due to inclement weather. Having said that, evidence of a widespread natural cycle to size 3.5 was observed on Wednesday. I expect ongoing natural avalanche activity with forecast weather on Thursday.
Snowpack Summary
Recent snowfall amounts since the weekend have been quite variable throughout the region. Generally speaking, ongoing moderate daily amounts and moderate to strong southwest winds have contributed to reactive wind and storm slab development. About 160cm below the surface lie buried weak surfaces that formed early February. These include a widespread surface hoar instability that, depending on aspect an elevation, may exist in combination with facets or crusts. These persistent weak layers have been reactive all week and remain a concern at all elevations. The weight of new snow, near-surface avalanches, sleds, and skiers may easily trigger these deeper weaknesses creating unexpectedly large and destructive avalanches.Large cornices have also formed and could act as triggers for slopes below.
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.
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.