Some snow in the forecast this week. Check back for updates as the storm progresses.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
Dry conditions persist on Monday, before a Pacific system brings light snow on Tuesday and Wednesday. Tues: 2-5 cm, Wed: 5-10 cm. Winds are expected to be moderate from the SW and the freezing level remains at valley floor. For more details check out https://avalanche.ca/weather.
Avalanche Summary
A cycle of naturally-triggered size 1-2 loose dry avalanches was reported on Friday. Most were on steep alpine shady aspects.
Snowpack Summary
Conditions are variable across the Purcells. Isolated wind slabs may be lurking behind ridges and ribs. Wind slabs or loose dry snow overlie old surfaces including surface hoar, near surface facets, and possible sun crusts on steep southerly aspects. Cold and dry weather is drying out the upper snowpack (through faceting). In parts of the Purcells, two prominent layers of surface hoar are reactive in snowpack tests. These are buried down 25-60 cm and may have a cohesive slab above. Shallow snowpack areas and moraine features may also have weak facetted snow near the ground that will require time and some warming to strengthen.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.