Avalanche Forecast

Issued: Jan 4th, 2019 5:29PM

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

Avalanche Canada ghelgeson, Avalanche Canada

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

Summary

Confidence

Moderate -

Weather Forecast

Moderate onshore flow will continue this weekend across the province maintaining flurry activity and bringing mostly cloudy conditions with a few sunny breaks. The next significant storm is expected to arrive Tuesday morning.FRIDAY NIGHT: Freezing level lowering to valley bottom, moderate southwest wind at most elevations with strong southwest wind at ridgetop, wind speed decreasing through the night, 2 to 6 cm of snow possible.SATURDAY: Broken cloud cover at dawn dissipating to just a few clouds by sundown, freezing level holding near valley bottom, light southerly wind with moderate gusts at ridgetop, no significant precipitation expected.SUNDAY: Overcast, freezing level holding near valley bottom, light southerly breeze at most elevations, a few centimeters of snow possible.MONDAY: Broken cloud cover, freezing level at valley bottom, west/southwest wind, trace of snow possible.

Avalanche Summary

On Thursday 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. On Wednesday avalanche activity was limited to natural and human triggered wind slab avalanches to size 2 on all aspects. We also received 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 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 was buried in mid-December. This interface is 100 to 150 cm below the surface and is now considered dormant. It is most prevalent on steep south-facing slopes in the alpine as well as north and east facing slopes between 1900 and 2300 m.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
Human triggered avalanches are the primary concern. Watch for newly formed and reactive wind fueled storm slabs which likely remain sensitive to human triggering. These will be most sensitive in lee terrain at and above treeline.
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 - Likely

Expected Size

1.5 - 2.5

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