Regions
Northwest Coastal.
Confidence
Fair - Timing of incoming weather is uncertain on Friday
Weather Forecast
Wednesday and Thursday: Mostly clear and dry, with freezing levels back to valley bottoms and moderate northwesterly winds. Friday: More snow is expected but the timing is uncertain. It could arrive as late as Friday evening. Freezing levels are expected to rise to 600m and winds shift to westerlies with the onset of precipitation.
Avalanche Summary
Numerous natural loose wet avalanches up to Size 2 with isolated Size 2.5s were observed during the warm and wet weather on Monday. Large glide avalanches from steep rock slabs were also observed; one was reported to be size 3.5.
Snowpack Summary
Overnight rain up to 1000m in the north, and alpine elevations in the south, likely melted surface hoar, settled surface facets, and froze into a crust. Glide cracks are opening and cornices are weakening.
Problems
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.