This bulletin was published using limited data from the Garibaldi South corner of the region. Regional snowpack variability likely exists, so be your own forecaster and make observations continually as you travel.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Light flurries are forecast for Tuesday. A mix of sun and cloud is expected on Wednesday and Thursday morning with light snowfall developing by Thursday evening. Ridgetop winds should remain mainly moderate from the northwest with freezing levels hovering around 500m for all 3 days.
Avalanche Summary
Explosives testing on Sunday produced storm slabs to size 2.5 in high elevation lee terrain. Most of the observed avalanche activity released within the new storm snow.; however, in at least 2 cases slabs released on a buried crust. At the time of publishing, no new avalanches were observed on Monday.
Snowpack Summary
5-10cm of low-density snow overlies 40-50cm of snow from last weekend's storm. These storm accumulations were shifted by strong winds into much deeper deposits in high elevation lee terrain. Below 1800m, there was much less wind effect and therefore less cohesion in the newly formed slab.Below 2200m, a hard rain crust can be found approximately 120cm below the surface. Recent tests suggest an improving bond at this interface. That said, in some areas the crust may remain reactive for some time after weaknesses within the storm snow have strengthened.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.