Regions
South Coast Inland.
Lingering wind slabs and cornices are a concern at higher elevations. Also be aware of direct sunlight weakening the surface snow on south-facing slopes.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
WEDNESDAY: Sunny in the morning with increasing clouds in the afternoon, light to moderate southwest wind, freezing level rising to around 1500 m.THURSDAY: Flurries increasing throughout the day with up to 5 cm in the north and up to 10 cm in the south, moderate southwest wind, freezing level rising to around 1300 m.FRIDAY: Another 5-10 cm of snow with freezing level rising to around 1300 m.
Avalanche Summary
On Monday, a few small slabs (10-20 cm deep) were reported in steep terrain in the northern part of the region. Over the weekend, a few size 2 natural slab avalanches were reported in the northern part of the region on a range of aspects around 2000 m.
Snowpack Summary
A thin sun crust has formed on solar aspects and the surface is wind affected in most exposed terrain. Southern parts of the region, such as the Coquihalla, received up to 100 cm of snow last week while northern regions received closer to 40 cm.The mid-February weak layers are now 80 to 120 cm deep in the southern part of the region and about 40 cm deep in northern parts of the region. These interfaces consists of wind hardened snow, facets, a sun crust on solar aspects, and surface hoar that is present at and below treeline. Some of these layers have been reactive in snowpack tests, but no recent avalanche activity has been reported on these layers. The mid and lower snowpack are well settled and strong.Variable winds in the past month have created cornices on many alpine ridgelines. They will become touchier as they grow in size, as temperatures rise, and as the strong late-winter sun shines down upon them on clear days.
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.