The next big change is on Sunday: Sunny warm weather will be the driver of avalanche problems.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Monday
Weather Forecast
The clouds will clear out Saturday afternoon, giving way to pleasant weather on Easter Sunday. Back to wet spring weather on Monday. SATURDAY: Isolated flurries (3-5cm possible) and occasional sunny breaks. Freezing level around 1400 m. Winds light southwesterly.SUNDAY: Clearing with some good sunshine. Freezing level rising to 1800 m in the afternoon. Winds light southerly. MONDAY: Snow (5-10cm) above 1500m. Winds 20-30 km/h from the south.
Avalanche Summary
On Thursday, explosives control work was able to trigger a Size 2 storm slab on a northwest aspect in the alpine near Whistler. Skiers were also able to trigger several Size 1 soft slabs in steep leeward alpine terrain. Expect avalanche activity to increase with the warm weather on Sunday.
Snowpack Summary
We've had 20-40 cm of recent storm snow above 1500m. Winds were moderate to strong from a variety of directions and have created fresh wind slabs in exposed terrain at treeline and above. On Sunday the sun will come out in full force - it's a good time to remember that cornices remain large in some areas and could trigger large avalanches when they fail (especially when warmed by the sun). 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.