Avalanche Forecast

Issued: Jan 5th, 2019 4:05PM

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

High -

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 10 cm of snow possible.MONDAY: Broken cloud cover, 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 Thursday and Friday a widespread natural avalanche cycle produced avalanches to size 2.5 on all aspects above 1000 m with crowns averaging 20 to 60 cm in depth. Control work produced avalanches to size 2.5 on all aspects above 1400 m. Three different avalanches to size 1.5 were accidentally triggered by skiers on north facing terrain between 2000 and 2250 m. On Friday a natural cornice failure impacted a northeast/east facing slope at 2300 m initiating a size 3 avalanche.On Wednesday avalanche activity was limited to dry loose avalanches in steep terrain. The exception was a report from the RMR backcountry 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 just north of the region. The large (size 3) persistent slab release was skier triggered below ridgecrest on a southwest aspect in the Connaught Creek area in Glacier National Park. Photo available here.

Snowpack Summary

Thursday and Friday's storm produced 30 to 60 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 80 to 140 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.
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.Expect slab conditions to change drastically as you move into wind exposed terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

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