Avalanche Forecast

Issued: Mar 22nd, 2014 10:20AM

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

ghelgeson, Avalanche Canada

Kootenay Boundary.

Cool temps and increased cloud cover should put the lid on solar activity on Sunday. Be aware that if the sun comes out, it could initiate cornice fall and natural slab failure surprisingly quickly.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Synopsis: The remnants of a very weak system pass over the region Saturday afternoon ahead of Sunday's strengthening ridge. A warm system approaches the coast Monday which should push high cloud into the region. There's potential for very high freezing levels on Tuesday, but it's still too far out to say. There's a chance for significant precipitation on Wednesday.Sunday: Freezing Level: 1000m - 1200m; Precipitation: Nil; Treeline Wind: Very light, Variable | Ridgetop Wind: Light, WestMonday: Freezing Level: 1000m; Precipitation: Nil; Treeline Wind: Light, NE | Ridgetop Wind: Light SWTuesday: Freezing Level: 1600m - 1900m; Precipitation: Nil; Treeline Wind: Light, SW | Ridgetop Wind: Light SW

Avalanche Summary

On Friday the strong sun heated the upper snowpack resulting in a natural cycle to size 2 on south and southeast facing slopes. Ski cuts on shady aspects produced avalanches to size 1.5. On Thursday a widespread natural avalanche cycle to size 2.5, averaging size 1.5 was reported. There were no reports of anything stepping down below the March 10th crust into the deeply buried persistent weak layers.

Snowpack Summary

20 - 40 cm of light density snow from last week rests on top approximately 30 cm of settled old storm snow. This makes for 50 - 70 cm on top of the March 10th crust. This crust is widespread to 2000m across the region, perhaps even higher on solar aspects. It's mostly supportable, we've received reports of it being as thick as 15cm in the south of the region, but it varies in thickness and supportability. As you head north in the region where the mountains are higher (and temperatures were colder when the crust was forming), this crust is less likely to exist.A facet/crust persistent weakness buried at the beginning of February, now down 70 to 200cm, has been highly variable in terms of reactivity but still shows 'sudden' results in some snowpack tests. In areas where the strong and supportive near surface crust exists, triggering this layer has become unlikely. That said, this layer is still difficult to trust and any avalanche at these deeper, persistent interfaces would be large and destructive.,

Problems

Storm Slabs

Tuesdays light density storm snow is settling out nicely in most of the region. Watch for sluffing on steeper features. In the north of the region the storm slab is likely more touchy. Consult the South Columbia Bulletin for details.

Be cautious as you transition into wind affected terrain.>Be cautious of sluffing in steep terrain.>Watch for clues of warming and back off if you observe, pinwheeling, sluffing off of cliffs and/or moist surface snow.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

The deeply buried weak layers still show "sudden" results in snowpack tests. Triggers for large avalanches on these layers include cornice falls, solar warming, or hitting the wrong place in a thin snowpack area.

Caution around slopes that are exposed to cornices overhead.>Avoid convexities or areas with a thin or variable snowpack.>Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Mar 23rd, 2014 2:00PM