Conditions will deteriorate over the day as cranking winds redistribute our loose snow into new wind slabs.
Weather Forecast
Thursday: Cloudy with scattered wet flurries bringing 2-5 cm of new snow by end of day. Snowfall increasing overnight. Moderate to strong southeast winds. Freezing level to around 1900 metres with alpine high temperatures around -1.Friday: Cloudy with continuing scattered flurries and another 2-5 cm of new snow. Moderate southwest winds. Freezing level to 1200 metres with alpine high temperatures around -7.Saturday: A mix of sun and cloud with isolated flurries and a trace of new snow. Light variable winds. Freezing level to about 900 metres with alpine high temperatures around -9.
Avalanche Summary
Reports from Sunday included a remotely (from a distance) triggered 25 cm deep storm slab (size 1) releasing with skier traffic on a steeper north-facing slope at around 2000 m in the Monashees. Several more natural size 2 storm slab releases were observed on very steep northeast-facing terrain at around the same elevation. These occurred during the peak of daytime warming.On Saturday there were numerous reports of size 1-2, loose wet avalanches on sunny, solar aspects involving the recent storm storm snow, as well as one report of a size 1.5 skier triggered slab (30 cm deep) on a northwest aspect at 2000 m.Last Friday there were reports of several skier triggered (size 1-1.5) avalanches from 15-25 cm deep on north through southeast aspects between 1700-2100 m.
Snowpack Summary
Recent light snowfalls have been followed by warm daytime temperatures and glimpses of sun, setting up a couple of thin storm snow layers over temperature and sun crusts at lower elevations and on south aspects. On shaded aspects at higher elevations, these snowfalls have buried and preserved a couple of surface hoar layers now found up to 30 cm deep. The deepest of these surface hoar layers has been the failure plane in several recent slab avalanches.New snow amounts taper with elevation and below 1800 m, minimal accumulations have buried a supportive crust on all aspects. This crust will likely break down with daytime warming, becoming moist in the afternoon. Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with a surface avalanche stepping down, large cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets.
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.