Avalanche Forecast
Issued: Dec 21st, 2018 4:44PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
kdevine,
Avalanche Canada
After a brief break in the stormy weather, wind and flurries are expected to continue through the weekend. Wind slabs are likely to be encountered at upper elevations and may be reactive to human triggering.
Summary
Confidence
Moderate - Due to the number of field observations.
Weather Forecast
FRIDAY NIGHT - Cloudy with isolated flurries, 2-4 cm / south winds, 30-50 km/h / alpine low temperature near -10°c. SATURDAY - Cloudy with scattered flurries, 5 cm / southeast winds, 30-50 km/h / alpine high temperature near -7°c. SUNDAY - Flurries during the day: 5 cm, Snow overnight: 5-10 cm / southeast winds, 40-60 km/h / alpine high temperature near -3°c, low temperature near -6°c. MONDAY - Cloudy with scattered flurries, 5-10 cm / southwest winds, 30-50 km/h / alpine high temperature near -4°c, low temperature near -7°c.
Avalanche Summary
Several small natural and explosives triggered avalanches (size 1-1.5) were reported in the region on Friday. On Thursday two explosives controlled avalanches were reported in the region. One was a size 2.5 north of Stewart, the other a size 3 on a north to northeast aspect at 1100-1300 m in the Ningunsaw area. On Wednesday, a size 2 human triggered avalanche was reported on a northwest aspect at 1350 m near Ningunsaw. This avalanche was remotely triggered (triggered from a distance) and failed on the surface hoar layer that formed in early December.
Snowpack Summary
5-15 cm of recent snow sits on a rain crust to approximately 1000 m. Above 1000 m this new snow is sitting on the 100-150 cm of storm snow that came in over the past week. Strong winds have likely affected open terrain at higher elevations and formed deep wind deposits in lee terrain. This 100-150 cm of recent storm snow sits on a weak layer that was a concern when the first waves of the storm hit the coast, but the strength of this layer has generally improved over the past week. This layer consists of surface hoar (feathery crystals), facets (sugary snow), and crusts that formed during the dry spell in early December. The surface hoar is most prevalent and has recently been reactive between 1100-1300 m in more northern portions of the region, and is something to keep in mind if you plan to travel to areas like Ningunsaw. Deeper in the snowpack, there are several crusts, including an early season crust with facets near the bottom of the snowpack.
Problems
Wind Slabs
Wind slabs may be reactive to human triggering at upper elevations, especially on steep slopes in lee terrain.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 22nd, 2018 2:00PM
