Northwest Coastal

Watch for areas where wind and storm snow have formed cohesive slabs above the recently buried crust/ surface hoar layer. These slabs have been reactive to both human and natural triggers. New snow and wind will increase avalanche hazard on Monday.

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Monday

TONIGHT: Increasing cloud. Ridge wind light, southeast. Temperature -12. Freezing level valley bottom.SUNDAY: Cloudy, flurries. Accumulation 5-10 cm. Ridge wind strong, southeast. Temperature -8. Freezing level valley bottom. Alpine Inversion.MONDAY: Snow. Accumulation 20-30 cm. Ridge wind strong, southwest. Temperature -4. Freezing level 500 m.TUESDAY: Snow. Accumulation 15-25 cm. Ridge wind moderate to strong, southwest. Temperature -2. Freezing level 500 m.

Reports from the Shames area on Thursday detailed "touchy" conditions with natural, remote and skier triggered avalanches up to Size 2 (including an involvement of a canine member of one group), between 1000-1400 m, on south to west aspects where the mid-January crust is quite prevalent. While explosive control work on easterly aspects between 1100-1330 m, produced several storm slab avalanches up to Size 1.5 which also failed on the recently buried, mid-January crust layer. Earlier in the week there were reports of natural and cornice triggered avalanches up to Size 2 failing on the mid-January interface while ski cut results produced storm slab avalanches to size 1.5 near ridge crest. And in the Bear Pass area numerous natural wind slab failures from Size 1-2.5 were observed on wind-loaded northerly features as well as Size 1.5-2.5 naturals between 600-1200 m that ran on the mid-December crust layer.

Approximately 50 cm of recent storm snow covers a widespread crust as well as surface hoar in isolated areas at mid elevations that were buried mid-January. Surface hoar is more likely to exist in sheltered areas at treeline and below with crust elsewhere. This interface has produced easy, sudden results in recent snowpack tests in the Shames area and also recent avalanche activity at upper treeline and alpine elevations.Professionals have also been monitoring a few mid-pack layers within the snowpack including a crust/ surface hoar layer that was buried early-January and now lies 60-100 cm below the surface, and a similar layer buried mid-December that now lies 80-120 cm below the surface. Both of these layers have been reactive in recent snowpack tests producing moderate to hard, sudden results and have also produced recent large, natural avalanches in northern parts of the region near Bear Pass.The lower snowpack is generally strong, with the exception of areas around Stewart and further north where a basal crust and facets exist.