Forecast sun and high freezing levels may increase the danger from loose wet avalanches and avalanches stepping down to the deeply buried weak layer.
Confidence
Fair - Timing or intensity of solar radiation is uncertain on Wednesday
Weather Forecast
Overnight and Wednesday: Warm air is expected to be trapped in the alpine overnight. The freezing level is expected to rise to near 2500 metres during the day. Some cloud and moderate Southwest wind are expected to develop during the afternoon.Thursday: Continued warm air at higher elevations. Wind becoming moderate Northerly and the freezing level dropping down to valley bottom Thursday night.Friday: Mostly clear with moderate Northwest winds and freezing levels rising to about 1000 metres.
Avalanche Summary
Moist or wet loose snow avalanches were reported up to size 1.0 on solar aspects. A couple of natural slab avalanches size 2.0 were reported from the Whistler backcountry on South-Southwest aspects that may have been triggered by the rapid settlement of the recent snow above the early February weak layer.
Snowpack Summary
Strong solar radiation quickly settled the 30-50 cm of recent cold low density new snow. Solar aspects becoming moist and then developing a thin melt-freeze crust during developing cloud in the afternoon. The prominent mid-February weakness, which is primarily a facet/crust combo (with surface hoar in some areas), is now 80-160 cm deep depending on wind exposure. Recent snowpack tests give variable results on this layer, but some observers are still reporting sudden "pops or drops" shears and continue to experience whumpfs. Previous strong winds created wind slabs in exposed lee and cross-loaded terrain, which are now hidden by the dry new snow. The mid and lower snowpack are generally strong and well-settled. Basal facets and depth hoar are likely to exist in some parts of the region; however, skier triggering has become unlikely.
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.