Watch for the formation of fresh wind slabs in the alpine Sunday afternoon as winds pick up out of the southwest.
Confidence
Low - Wind effect is extremely variable
Weather Forecast
A storm impacts the coast Sunday which should start to erode the ridge of high pressure that has been plaguing the province for the last week. A bit of snow may venture into the region Sunday with potential for another wee storm Tuesday night into Wednesday. SATURDAY NIGHT: Freezing level at valley bottom, light west/northwest wind in the alpine, no significant precipitation expected.SUNDAY: Scattered cloud cover, freezing level at valley bottom, moderate to strong southwest wind in the alpine, no significant precipitation expected during the day, potential for a few centimeters of snow Sunday night.MONDAY: Broken cloud cover, freezing level near valley bottom, light to moderate west wind, trace of precipitation possible.TUESDAY: Broken cloud cover, freezing level near valley bottom, moderate to strong west/southwest wind, trace of precipitation possible.
Avalanche Summary
Several size 1.5 natural wind slab avalanches were reported from a steep south through southwest facing alpine feature on Friday.
Snowpack Summary
Recent moderate winds have created wind slabs in the alpine and isolated treeline areas.There are two layers of surface hoar (weak feathery crystals) being reported in the top 15-30cm. The surface hoar is most prominent at treeline, but it may be found in sheltered alpine areas. Both of these layers may be associated with a sun crust on south aspects in some areas.Another notable feature in the snowpack is a combination of a crust and faceted (sugary) snow found at or near the base of the snowpack. This layer is most prominent in the alpine.The early season snowpack is highly variable in the Purcells. Total snowpack depths vary greatly throughout the region with anywhere between 70 and 150 cm in the alpine and tapering rapidly at treeline and below. In shallow snowpack areas, the bottom half of the snowpack is reportedly weak and "hollow" feeling on shady aspects due to sugary, faceted snow.
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.