Regions
Northwest Coastal.
Pockets of reactive wind slab remain a concern for wind-exposed alpine and treeline areas. New snow and south west wind on Monday will heighten avalanche danger.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
We're looking at a small amount of snow through Monday and some lingering flurries for the week as temperatures gradually warm up.MONDAY: Cloudy, flurries. Accumulation 5-10 cm. Ridge wind moderate to strong southwest. Temperature -6. Freezing level 400 m with an above freezing layer (AFL) from 1200m to 1700m. TUESDAY: Cloudy with some flurries (2-5 cm possible). Ridge wind moderate south west. Temperature -5. Freezing level 500m with an AFL from 1200m to 1700m. WEDNESDAY: Cloudy with isolated flurries. Ridge wind moderate from the south. Temperatures -4. Freezing level 400m with an AFL from 1100m to 1900m.
Avalanche Summary
On Thursday an isolated wind slab release (size 1.5) was observed on an actively wind loaded, steep terrain feature in the northern part of the region.
Snowpack Summary
Cold temperatures and strong winds (from the south east, and more recently from the west) have affected the surface snow over the past week, scouring some slopes down to an old crust and forming hard deposits in many other areas. There are some lingering wind slabs, found on a variety of old surfaces including a thick melt-freeze crust that formed in mid-December. In non-wind affected terrain, 20-40 cm of unconsolidated (aka faceted or 'sugary') snow overlies the mid-December crust layer. This snow has been sluffing in steep terrain.Beneath the mid-December crust the snowpack is reported to be generally strong with the possible exception of areas around Stewart and northern parts of the region where the late-October, basal crust can be found near the base of the snowpack. Weak sugary snow may exist around this basal crust and could be triggered from shallow snowpack areas.
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.