Avalanche Forecast

Issued: Jan 22nd, 2014 8:55AM

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

ccampbell, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Thursday through Saturday: A mix of sun and cloud with no precipitation expected. Light alpine winds. Freezing levels reaching 3000m or higher, with alpine temperatures reaching +5C, but a temperature inversion should keep valley bottoms cooler.

Avalanche Summary

Reports from Tuesday include a recent Size 2 natural storm slab avalanche that ran on a buried crust on NE aspect at 900m. Otherwise no new avalanches have been reported.

Snowpack Summary

Approximately 5 to 25cm (elevation and drainage dependant) of recent storm snow sits on various old snow surfaces including crusts. Previously strong winds have resulted in highly variable snowpack depths in exposed areas with deep drifts, scoured areas, and sastrugi. The surface snow is likely undergoing melt-freeze cycles particularly on sun-exposed slopes and at lower elevations. The surface hoar persistent weakness buried early January is most prevalent down approximately 50cm on sheltered slopes at treeline. Professionals continue to keep an eye on the basal facets which can be found down near the ground.

Problems

Wind Slabs

Thin wind slabs below ridge rests and behind terrain features should be manageable. Be aware off the potential for deep hard wind slabs if you're sizing up bigger terrain in the alpine.

Be cautious as you transition into wind affected terrain.>Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>Start on small terrain and slope-cut the top of slopes before riding them.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

Two weaknesses have the potential to surprise folks: Surface Hoar around 50 cm below the surface and very weak basal facets near the ground. Vigilant slope by slope evaluation and/or a modest terrain approach are appropriate at this time.

Avoid convexities or areas with a thin, rocky or variable snowpack.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Be aware of the potential for large, deep avalanches.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

4 - 7

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