Avalanche Forecast

Fair - Intensity of incoming weather is uncertain

Light precipitation anticipated for the Duffy area overnight Tuesday, while the Coquihalla may see moderate amounts into Wednesday. Strong winds from the NW will persist through Wednesday, with a wind warning in effect. A weak ridge of high pressure builds bringing dryer, cooler conditions on Thursday. Friday brings moderate precipitation through the day into Saturday morning.

Coquilhalla Area: Several natural size 1 avalanches ran in the morning on steep solar aspects. On Sunday a skier triggered size 1 was reported. This occurred on an East aspect, @ 1845m. The crown was 20cm deep, and 10m wide. Another skier triggered avalanche size 1.5 occurred on a North aspect @ 1460m. This was below treeline in a gully feature. Both avalanches failed on the buried weak layer that exists below the new storm snow. No injuries reported. Duffy Lake area: Natural loose snow sluffiing within the new storm snow from steep terrain features. Last Saturday a size 2 rider triggered avalanche was reported, to see more details visit our incident report database: http://www.avalanche.ca/cac/library/incident-report-database/view/ffa0801e-2d0e-48e8-b480-5b6068d5a8bDanger ratings in the alpine and treeline are based on snowfall amounts of 10 or more cms, with strong winds. I expect the Duffy region to see less, therefore the danger ratings may be more Considerable.

Over the past few days 20-30 cm of new snow fell over the Duffy Lake area. The Coquihalla has seen up to 50 cm. This new snow has buried a variety of old snow surfaces that formed during a sunny dry spell over the past 2 weeks. The old surfaces include: melt-freeze crusts on all aspects below 1700m and on steep solar aspects higher up, surface hoar (feather like crystals), old wind slabs, and facets (sugary crystals), which exist on north aspects as well as around crusts. The surface hoar seems to be most prominent in sheltered treeline locations and below, and most likely found in the north and central parts of the region. We may see these buried weak layers become naturally reactive with forecast snow and wind, and likely susceptible to rider triggers. Generally below this sits a well settled snowpack, with treeline snowpack depths near 250cm. For insight on incremental loading, and the "Tipping Point" check out our latest Forecaster's Blog. To view recent photos of this buried surface hoar in the Coquihalla area please click this link:http://www.avalanche.ca/cac/library/avalanche-image-galleries/avalanches2012