Spring conditions typically means the hazard is highest during the heat of the afternoon. Cornices and loose wet sluffing are spring problems which can be expected on Saturday. Wind slabs may also still be lingering in high elevation leeward terrain.
Weather Forecast
The warm ridge of high pressure persists through the weekend. Saturday and Sunday are expected to be sunny with light alpine winds and afternoon freezing levels around 3000m. Unsettled conditions are expected for Monday with a mix of sun and cloud, and the possibility of light scattered flurries. Moderate southwest winds are expected in the alpine and freezing levels are expected to drop to around 2200m.
Avalanche Summary
On Thursday, a natural cornice fall triggered a size 2 slab on the slope below. A few natural size 2 storm slab avalanches were also reported on high northern aspects. Glide avalanches were reported on steep north facing convexities at treeline. On Wednesday, natural loose wet avalanches up to size 1.5 were reported. Skiers and explosives were triggering wind slabs up to size 1.5 in leeward features and on steep rolls. Small natural cornice falls were reported in the afternoon. With warm and sunny conditions continuing, spring avalanche problems are expected to be the primary concerns. Loose wet avalanches and large cornice falls are expected throughout the forecast period. Wet slabs may be possible on steep south facing slopes while the temperatures remain high and overnight recovery is poor. Lingering wind slabs may also still be a problem on high elevation north aspects.
Snowpack Summary
Little to no overnight recovery was reported on Friday morning leaving a moist or wet snow surface on all aspects and elevations. The early-April crust layer is typically down 10-20cm and is reported to be breaking down due to the warm conditions. Prior to the warming, the recent storm snow had been shifted by strong southerly winds into wind slabs in wind-exposed terrain. These wind slabs may still be lingering in high north facing terrain. The mid and lower snowpack are generally strong and well-settled. Cornices are huge and will become weak with warming and solar radiation.
Problems
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.
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.
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.