Avalanche Forecast

Issued: Jan 4th, 2019 4:52PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs.

Avalanche Canada dsaly, Avalanche Canada

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Natural avalanche activity is decreasing, but the chance for human triggered avalanches remains likely.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

FRIDAY NIGHT: Cloudy with isolated flurries, trace to 10 cm snow. Light to moderate southwest wind. Freezing level dropping below 1000 m.SATURDAY: Flurries, up to 5 cm snow. Moderate southeast wind. Freezing level 1500 m.SUNDAY: Flurries, 5-10 cm snow. Moderate southwest wind with strong gusts. Freezing level below 1000 m.MONDAY: Unsettled as another system approaches, trace accumulation. Light northwest wind transitions to strong southwest. Freezing level below 500 m.

Avalanche Summary

Unfortunately, a skier was killed in an avalanche near Pemberton on Thursday. There is limited information regarding the accident at this time.The new snow continues to be reactive with explosives triggering storm slab avalanches to size 2 on Friday. On Thursday, to the north of the region, natural storm slab avalanches to size 3 were reported. Closer to the Duffey, the storm slab was most reactive in steep and unsupported terrain and explosives triggered storm slab avalanches to size 2. In the south, near the Coquihalla, wet avalanches size 2-2.5 running in steep terrain were reported.Last Sunday, several skier and snowmobile triggered avalanches were also reported on the Dec 26 layer. There was a report of two skier triggered avalanches in the Zoa peak area near Coquihalla Summit. These were both reported to be up to size 2 and running on a layer of surface hoar buried 40-60 cm deep (now closer to 70-100c m down) on a north aspect at treeline. See the MIN report here. An additional avalanche incident was reported by snowshoers in Manning Park. It is suspected to have run on the same weak layer. See the MIN report here.

Snowpack Summary

Over the last week, 40-100 cm storm snow accumulated through the region. This new snow rests on two variable weak layers (from Dec 26 and Jan 1). Now down 70-100 cm, there is a crust on steep south and west aspects and surface hoar in more sheltered terrain. The surface hoar layer is reported to be most prevalent in the southern part of the region (e.g. Coquihalla Summit and Manning Park) at the upper end of treeline on north and east aspects. In the north part of the region, another weak layer composed of facets and/or surface hoar is buried 100 to 150 cm deep. This weak layer appears most prominent around treeline (up to 2000 m). There have not been reports of avalanche activity on this layer for the past week, but field observations suggest slab avalanches may still be possible on this layer where it exists.

Problems

Storm Slabs

An icon showing Storm Slabs
40-100 cm of recent snow and wind has formed slabs around the region. Expect to find deeper and more sensitive deposits in wind-loaded areas.
The new snow will require several time to settle and stabilize.Be cautious as you transition into wind affected terrain.Use caution in lee areas. Recent snowfall mixed with wind loading has created storm slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1.5 - 3

Valid until: Jan 5th, 2019 2:00PM

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