Regions
Northwest Coastal.
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
Tonight and Tuesday: Moderate snowfall - Approximately 5cm overnight and an additional 5-15cm on Tuesday. The freezing level (FL) is around 500m and winds are moderate from the S-SW. Wednesday: Unsettled conditions with convective flurries - 5-10cm. FL is near 500m. Winds easing to light from the south. Thursday: Mainly cloudy with light flurries. No significant accumulation.
Avalanche Summary
There was one report of a Size 2.5 natural slab avalanche on a SW aspect along the highway corridor west of Terrace. The crown was reported to be 45-70cm deep. Otherwise there were no new observations.
Snowpack Summary
The soon to be buried snow surface includes a sun crust on southerly aspects, surface facets or surface hoar in cool shady areas, and pockets of wind slab in exposed terrain. A variety of potential weak layers exist between 60 and 120cm deep. These include surface hoar or facets. There has been no recent activity on these layers but they could wake up with heavy triggers like a large cornice chunk or a snowmobile digging its track in. Cornices in the region are reported to be very large and potentially unstable.
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.