The hazard may be higher than expected on solar aspects if the sun comes out and the temperature goes higher than forecast. Pay careful attention to cornice hazard.
Confidence
Fair - Freezing levels are uncertain
Weather Forecast
Synopsis: THe cold front that tracked through southern BC today was a bit of a let-down for precipitation in the Sea to Sky region.Tonight: Cloudy with flurries, freezing level at valley bottom, ridge top winds from the west, light occasionally moderate.Thursday: Cloudy with sunny periods, no precipitation in the forecast, freezing level around 900 metres, winds light, from the west.Friday: Sunny with some cloudy periods, no precipitation, freezing level around 900 metres, light ridge top winds from the east.Saturday: Cloudy with flurries, trace of precipitation, freezing level around 1100 metres, ridge top winds, light from the south west.
Avalanche Summary
Reports of surface sluffing in steep terrain, several reports of size 1 skier triggered wind slabs, recent natural avalanche cycle up to size 2 to in the storm snow. Moist snow to ridge tops on solar aspects during the day.
Snowpack Summary
Up to 45 cm of recent storm snow is sitting on a variety of layers. A well developed sun crust has formed on solar aspects and, prior to this storm, surface hoar formed on shady, sheltered slopes. At lower elevations, a melt-freeze (or rain) crust can be expected in most areas. Moderate to strong SW winds have formed wind slabs on lee slopesBelow the storm snow, the upper snowpack is generally well settled from the recently warm weather. Two persistent weak layers remain a concern but these problems are becoming more isolated. Before the storm, the early-March crust/facet layer was down roughly 1m and the early Feb. layer is down 1.5m or more. These layers are now deep enough that human-triggering is unlikely, but smaller avalanches or cornices failures have the potential to step down to these layers, and,.... cornices are definitely getting larger these days.Freezing levels have been cycling between valley bottom and 1500-2000m, and low elevation terrain saw significant rain last weekend. The snowpack at lower elevations has been generally stable but wet snow or rain may destabilize the upper layers of the snowpack.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.