Lingering uncertainty about the ability to trigger deep persistent weak layers requires a cautious approach to terrain. Avoid thick to thin snowpack transitions, and have a healthy respect for what is above you.
Weather Forecast
TUESDAY Temperatures warming throughout the day, with freezing levels at valley bottom. Light SW windsWEDNESDAY Flurries up to 10cm with moderate SW winds building to strong overnight. Freezing levels to 1600mFRIDAY Flurries up to 5cm with Moderate to Strong W winds. Freezing level to 1600m.
Snowpack Summary
The Alpine is highly wind affected from strong west winds. Snowpack at treeline is comprised of 20-30cm of new wind slabs above many layers of old wind slabs. These have bonded well to create a strong mid pack, though the bottom of the snowpack remains facetted and weak. Snow cover is variable, with a treeline average of 160cm at Cameron Lake.
Avalanche Summary
Recent snow and winds led to a limited natural cycle on west aspects on the weekend, with avalanches to size 2 observed along the Akamina Parkway and cornice fall triggering a size 2.5 in Red Rock Canyon. Small skier controlled windslabs were reported in the Castle Mountain region.
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.