Observations were limited on Friday and uncertainty exists with forecast freezing levels. Be alert to conditions that change with elevation and make observations continuously as you travel.
Confidence
Fair - Freezing levels are uncertain on Saturday
Weather Forecast
Saturday: Light snowfall becoming moderate overnight / Moderate to strong west winds / Freezing level at 1200mSunday: Light snowfall / Light to moderate northwest winds / Freezing level at surfaceMonday: Light snowfall / Light southwest winds / Freezing level at 900m
Avalanche Summary
On Thursday there was a widespread natural avalanche cycle which included several size 3 slabs. Some released to ground below 1500m where the snowpack had become saturated.
Snowpack Summary
Strong southwest winds, heavy snowfall, and warm temperatures in recent days have formed deep and cohesive storm slabs at treeline and above. Widespread cornice development has also taken place. At lower elevations rain has continued to penetrate the snowpack, and below 1400m the snowpack is reported to be isothermal. The recent storm snow overlies a weak layer of surface hoar or a sun crust that were buried on March 10th. Some areas had strong winds before the surface hoar was buried, so its distribution may be specific to sheltered and shaded terrain features. There is still concern for the buried layer of surface hoar from February 12th that is now down more than 1.5m in most places. Although less likely, the new load of snow and wind may overload this deeply buried weak layer in isolated terrain.
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.