Purcells

Check out the recent forecasters blog on current conditions & decision making: http://bit.ly/sF10fT

Fair - Timing, track, or intensity of incoming weather is uncertain on Wednesday

Tue: Scattered high clouds, Alpine winds Moderate, SW. 1500m Temp: H: -4, L: -13Wed: Increasing cloud. Snow, increasing intensity after noon. 5 - 10 cm expected. Alpine Winds Strong, SW, switching W around lunch time. 1500 Temp: H: -4, L -10

Skier remote, skier controlled and skier accidental avalanches were reported from all aspects and elevations Sunday. The southern half of the region received a bit more snow Saturday night into Sunday which initiated a natural avalanche cycle producing avalanches to size 2.5. Avalanches associated with this cycle were observed on SW, S & E aspects. (I suspect all aspects were involved.) In summary, large avalanches continue to be easily triggered by skiers & sledders.

Another 8cm of dry light snow overnight brings the new storm total to about 20-25 cm of dry light snow above the recent stiff windslabs. The upper snowpack structure is very complex. There are buried layers of surface hoar, buried melt-freeze crusts, and some buried crusts with facets. These weak sliding layers are buried anywhere from 40 - 80 cm by several different storm layers. There are some shears in the storm layers on decomposed and fragmented snow crystals. As the snow above the surface hoar layers settles into a cohesive slab, we are seeing easier and more sudden shears that are a bit deeper. The surface hoar is more likely to produce wider propagations, and lower angle fractures in areas where it is associated with a crust. The crust has been reported to be 2-3 cm thick in some areas. The mid-pack is generally well settled. Basal facets have not been reactive, but operators continue to monitor this layer in tests. Triggering this deep persistent weak layer is unlikely, but shallow snowpack areas or shallow weak areas adjacent to deeper wind loaded slopes are the most suspect locations.