Wind slabs and cornices are the main concerns right now. Carefully assess terrain before committing to bigger lines.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Tuesday
Weather Forecast
We're back to wet spring weather on Monday, and continuing throughout the forecast period. MONDAY: Rain (5-10mm) falling mostly after noon, with wet snow (5-10cm) above 1500m. Winds 20-30 km/h from the south.TUESDAY: Wet snow or rain (10-20mm / cm). Freezing level around 1500 m. Winds moderate southwesterly.WEDNESDAY: Rain (10-15mm) up to 1600m. Winds strong southerly.
Avalanche Summary
On Sunday, skiers were able to trigger Size 1 wind slabs near Whistler, running in recent storm snow. Small, loose wet avalanches were also reported during the heat of the day on Sunday.
Snowpack Summary
We've had 20-30 cm of settling storm snow above 1500m. Warm temperatures on Sunday (+4 at treeline) likely resulted in a melt-freeze crust on all aspects and elevations at treeline and below. Lingering wind slabs may still exist in exposed terrain features at treeline and above. Cornices remain large in some areas and could trigger large avalanches when they fail. The fatal accident near Lions Bay a week ago illustrates the danger of cornices breaking off, and the large avalanches they can trigger.
Problems
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.
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.
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.