http://www.pc.gc.ca/apps/scond/cond_e.asp?oid=30728&opark=100092Large natural avalanches continue to be observed out of solar alpine start zones late in the day. The most significant slide covered the road near the Weeping Wall (Mt Cirrus) on Saturday.
Weather Forecast
Temperatures remaining cool, but have the potential to reach fluctuate significantly over the course of the day. Minimal snowfall expected, light winds, and clear skies to continue through to midweek.
Snowpack Summary
Varied storm snow amts: 10-15cm in the Icefields, 40cm near Mt Wilson, and 30cm north of Beauty creek is sitting on the weak and facetted persistent slab at mid snowpack. Reverse loading from a northerly flow has cross-loaded Alpine features.
Avalanche Summary
Widespread avalanche cycle throughout the forecasted region with numerous to size 3.5 over the last 3 days from all aspects. All elevations saw significant propagation with debris often reaching valley bottom even from ALP start zones. Several large natural avalanches were observed off Mt Cirrus late in the day on Friday.
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.