Expect conditions to be very aspect dependant. It is Winter on Northerly aspects with dry snow and very large cornices. And it is Spring on Southerly aspects with moist snow above old crusts.
Confidence
Fair - Timing or intensity of solar radiation is uncertain on Saturday
Weather Forecast
Overnight and Saturday: Mostly clear overnight with alpine temperatures dropping down to -13.0. Light Easterly or Northeasterly winds are expected. Freezing levels rising to about 1200 metres during the day.Sunday: A ridge of High pressure will be centered over the Interior ranges bringing Light Southwest winds and daytime highs of about -6.0 in the alpine. Strong solar radiation and freezing levels rising to about 1300 metres.Monday: The ridge is expected to move Eastwards during the day, but mostly sunny conditions should continue during the day.
Avalanche Summary
Natural avalanches, cornice falls, and skier controlled avalanches were reported up to size 2.0 that did not release below the storm snow. Expect loose moist snow to fall naturally from steep terrain and cliff bands that may trigger the storm snow where it is moist and sitting on a previous crust.
Snowpack Summary
Moist snow can be found on solar aspects up to about tree-line. Cold clear nights are expected to develop new melt/freeze crusts in areas that became moist. There is close to a metre of storm snow that has fallen in the last few days. This storm slab is sitting above variable surfaces that include crusts and moist layers that were deposited during the wet (Pineapple Express) storm last week. Periods of strong winds in the alpine transported the storm snow into thick pockets of wind slab that may take several days to settle and bond to the old surface. Cornice growth has been reported to be extensive and weakly bonded. Natural cornice falls are a concern, especially if we see periods of strong solar radiation. Cornice falls or storm slabs in motion may step down to the weak layer of buried surface hoar from March 10th.
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.
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.