Regions
South Coast Inland.
Forecast snowfall amounts are extremely variable throughout the region. Pay close attention to how much snow falls in your riding area and be prepared to back-off to simple terrain.
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Saturday
Weather Forecast
Saturday: 10-20cm of new snow / Strong southwest winds / Freezing level at 1800mSunday: Clear skies / Light and variable winds / Freezing level at 1900mMonday: Clear skies / Light and variable winds / Freezing level at 2400m
Avalanche Summary
Explosive control work in the Duffey Lake area on Wednesday produced a size 3 persistent slab avalanche that propagated over 200 m wide, failing on the late March weak layer. This result was on a west to southwest aspect between 2100-2200 m. No new avalanches were reported on Thursday. I would expect expect a new round of wind slab activity on Saturday in response to new snow and wind. Naturally triggered loose wet avalanches, cornice falls and intermittent persistent slabs should be on your radar with warming and solar radiation forecast for Sunday and Monday.
Snowpack Summary
New snow and wind on Saturday are expected to form fresh wind slabs in upper elevation lee terrain. The new snow is expected to overlie settled storm snow on shaded aspects above 2000m and a melt-freeze crust in most other areas.A weak layer consisting of surface hoar, facets, and/or a melt-freeze crust from late March is now buried about 50 to 100 cm. This layer is spotty in its distribution and has recently produced large and destructive avalanches. It is mostly likely to be problematic on west, north, and east aspects between 1900 m and 2250 m.The mid and lower snowpack are well-settled and strong.
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.