Avalanche Forecast
Issued: Jan 19th, 2019 4:22PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
dsaly,
Avalanche Canada
Strong winds are redistributing falling snow and building wind slabs. Expect the deeper and more sensitive deposits in lee features and cross-loaded terrain. In areas accumulating over 25 cm new snow, avalanche danger is Considerable.
Summary
Confidence
Low - Forecast snowfall amounts are uncertain
Weather Forecast
SATURDAY NIGHT: Flurries, trace to 10 cm snow. Strong to extreme southwest winds. Alpine low temperature -7C.SUNDAY: Cloudy with scattered flurries, around 5 cm expected bringing new snow totals to 10-20 cm. Moderate west winds. Alpine high temperature -7C.MONDAY: Flurries, 5-15 cm accumulating by end of day. Moderate southwest winds gusting to extreme. Alpine high temperature -7C.TUESDAY: Snow, 5-15 cm, Moderate to strong west winds. Alpine high temperature -4C.
Avalanche Summary
On Friday, a size 2 avalanche was observed on a southeast aspect just below the ridgeline (see MIN report here). Recent winds have been south-south easterly, however cross-loading and variable wind transport have likely contributed to winds slabs on all aspects in the alpine and treeline.A large (size 2) persistent slab avalanche was remote (from a distance) triggered in the Kispiox area on Tuesday. It released over a buried layer of faceted (sugary) snow on a mellower (30 degree slope) southeast aspect at 1680 metres. This avalanche stands out from recent reports for the presence of a persistent weak layer at the failure plane, as well as for its remote trigger on a fairly mellow slope. Although it appears to be an isolated incident, it highlights the presence of a buried persistent weak layer that may remain preserved in northern parts of the region. Images of the slide suggest that wind loading was another contributing factor.
Snowpack Summary
New snow is accumulating above mainly wind-affected and faceted (sugary snow) surfaces but also over a new weak layer of surface hoar in more protected areas. Last weekend's storm brought rain up to 1500 m, so the new snow is accumulating above a probable combo of surface hoar over rain crust below this elevation. Below this new snow interface, 25-50 cm of wind-redistributed storm snow from last weekend is expected to have formed a good bond with the underlying snowpack.A few buried weak layers that consist of surface hoar (feathery crystals) and/or faceted (sugary) snow may exist in some sheltered areas. The upper layer is about 35-60 cm deep and is a possible culprit in the Kispiox avalanche noted above. The next layer is likely 65-90 cm deep. The lower one is now approximately 100-150 cm deep.The bottom 30 to 50 cm of the snowpack consists of facets and crusts, particularly in areas where the snowpack is thin. It may be possible for storm slab avalanches to scrub down to ground in thin snowpack areas, resulting in large avalanches.
Problems
Wind Slabs
Overnight snowfall and strong winds are expected to build wind slabs on northeast to northwest aspects and in cross-loaded terrain. Northern parts of the region may hold larger old wind slabs sitting over a layer of preserved surface hoar.
Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.Expect quicker snow accumulation and slab formation to occur at higher elevations.Be aware of the potential for touchier old wind slabs over surface hoar in the north of the region.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 20th, 2019 2:00PM
