Regions
Banff Yoho Kootenay.
While it is tempting to ski steeper lines, keep in mind the potential for power sluffing and the existence of hard windslabs. It is NOT open season on steep terrain.
Weather Forecast
The precip has been postponed until late Monday. By Weds expect about 10cm in Lake Louise. Temps will stay in the -10 range and wind is expected to be light from the West.
Snowpack Summary
Wind effected and faceted surface snow snow overlies three mid- pack weak layers 100-130cm down that are gaining strength. These layers continue to produce moderate, sudden planar test results on surface hoar in deep tap tests, and hard to no results with standard compression tests. Thin snowpack areas are degrading/facetting in the cold.
Avalanche Summary
2 responses to avalanche accidents today. The 1st involved a skier boot packing up a steep couloir near Taylor Lake who triggered a size 2 windslab. The skier was not buried but sustained serious injuries. The 2nd skier near Floe Lake was entrained in a large sluff (surface facets) and was dragged through trees and also sustained serious injuries.
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.