Storm snow and strong SW winds in the next 36 hours will increase avalanche danger. Be aware of changing conditions.
Weather Forecast
Flurries are expected today with the main bulk of the storm bringing 25-30cm tonight and early Friday morning. Freezing levels should remain below 1300m with moderate to strong SW winds. Saturday will be mainly cloudy with isolated flurries, freezing levels remaining around 1300m.
Snowpack Summary
This past week 70cm of snow fell at 1900m and is settling into a slab, which sits on the November 13 crust. Tests on this interface, and a stellar crystal layer above, indicate that in some areas the slab may have a poor bond and could be triggered by a person. Pockets of windslab are present in the immediate lee of alpine and ridge-top features.
Avalanche Summary
No new avalanche activity reported from yesterday.
Confidence
Due to the number of field observations
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.