The likelyhood of natural triggering has decreased with cool temps. Preserved weaknesses in the mid snowpack still warrant a cautious approach in some areas, particularly at treeline.
Weather Forecast
Arctic air will dominate with few clouds, light winds, highs near -10 and lows near -20C. Warm, wet, pacific air is forecast to over-ride the arctic air Wednesday morning. This system may bring up to 25mm of precip with moderate winds and temperatures nearing -5C.
Snowpack Summary
15 cm of new snow arrived last weekend with light N winds. This sits over previous wind slabs formed by 40cm of snow pushed around mainly by strong SW winds. Mid-pack persistent weak layers, mainly preserved Jan 7 surface hoar down 40 to 60cm and the rotten Dec 15 facets sitting just below are still a concern but remain stubborn to triggering.
Avalanche Summary
A good look around today with clear skies. Saw two naturals in the Maligne area in the morning. A few notable avalanches seen through the tenure most of which were at least 48 hrs old; generally windslabs in the alpine to sz 2.5 and a few persistent slabs in the low alpine.
Confidence
Intensity of incoming weather systems is uncertain on Wednesday
Problems
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.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.