Avalanche Forecast

Issued: Jan 5th, 2019 4:34PM

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

Avalanche Canada ghelgeson, Avalanche Canada

Human triggered avalanches are the primary concern Sunday. The best and safest riding will be found in the trees on slopes that have soft snow without any slab properties. Stay relatively conservative as the snowpack continues to adjust.

Summary

Confidence

Moderate -

Weather Forecast

Moderate onshore flow will continue Sunday across the province maintaining flurry activity and bringing mostly cloudy conditions with a few sunny breaks. SATURDAY NIGHT: Freezing level holding near valley bottom, light southerly wind at most elevations with strong southerly wind at ridgetop, 1 to 5 cm of snow possible.SUNDAY: Overcast, freezing level holding around 700 m, light southerly breeze at most elevations with strong south/southwest wind at ridgetop, 3 to 8 cm of snow possible.MONDAY: Broken cloud cover at dawn thinning to just a few clouds in the late afternoon, freezing level at valley bottom, light west/northwest wind with moderate gusts at ridgetop, trace of snow possible.TUESDAY: A few clouds at dawn with cloud cover steadily increasing through the day, freezing level at valley bottom, light variable wind for most of the day at all elevations, trace of snow possible.

Avalanche Summary

On Saturday control work produced storm slab avalanches to size 2 with crowns up to 40 cm in depth. A skier accidentally triggered a small storm slab on a southwest facing slope at 1600 m.On Thursday and Friday a widespread natural avalanche cycle produced avalanches to size 2.5 on all aspects above 1200 m. A natural size 3 avalanche was reported from a south facing feature at 2400 m. We received a report from the RMR backcountry on Wednesday where a group triggered a size 2.5 avalanche on a steep south/southeast facing terrain feature immediately lee of ridgecrest at approximately 2250 m. A ski was lost, but everyone made it out okay. Photos and additional details can be found here.On December 31st a notable avalanche occurred in the neighboring Glacier National Park region. The large (size 3) persistent slab release was skier triggered below ridgecrest on a southwest aspect in the Connaught Creek area. Photo available here.

Snowpack Summary

Thursday and Friday's storm produced 40 to 80 cm of new snow accompanied by moderate to strong wind out of the south. A 2 mm "zipper" (melt/freeze/mist) crust under the new snow has been reported in the mountains surrounding Revelstoke. Underneath the most recent storm snow is the 30 to 40 cm of snow that fell last weekend. There are a few reports of spotty surface hoar underneath all of this new snow, but for the most part the storm snow does not sit on any kind of persistent weak layer and is expected to rapidly settle this weekend as as precipitation slows and temperatures cool.An aspect dependant mix of facets, surface hoar, and sun crust buried in mid-December, now 100 to 150 cm below the surface, is considered dormant at this time.The lower snowpack is generally strong and settled, with a crust that formed in late October near the bottom of the snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs
Watch for newly formed and reactive wind fueled storm slabs which may remain sensitive to human triggering, especially in the alpine. These will be most sensitive immediately lee of ridgecrest and behind mid-slope terrain features like ribs.
Expect slab conditions to change drastically as you move into wind exposed terrain.Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Jan 6th, 2019 2:00PM

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