Avalanche Forecast

Issued: Mar 18th, 2014 9:31AM

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

jlammers, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Wednesday

Weather Forecast

Wednesday: Light snowfall intensifying overnight (up to 10cm) / Moderate to strong westerly winds / Freezing level at 1300mThursday: Continued flurries with possible sunny breaks / Moderate westerly winds / Freezing level at surfaceFriday: A mix of sun and cloud / Light northwest winds / Freezing level at surface

Avalanche Summary

Avalanche control on Monday produced numerous storm slabs to size 2 which occurred on a variety of aspects at treeline and in the alpine.

Snowpack Summary

Up to 40cm of recent storm snow was blown by variable strong winds into deeper deposits in lee terrain. These recent accumulations overlie crusts on previously sun-exposed slopes and surface hoar in shaded terrain. Rain at lower elevations has saturated the snowpack. Where the air temperature has dipped below freezing, lower elevation surfaces may exist as a refrozen crust.Below the new snow, 60-100cm of settled snow sits above buried surface hoar and crusts. The deeper facet/crust persistent weakness buried at the beginning of February, now down 70 to 160cm, has been highly variable in terms of reactivity but still shows 'sudden' results in snowpack tests. Needless to say, this interface is still very difficult to trust and any avalanche at these deeper, persistent interfaces would be large and destructive.Weak basal facets exist in many areas, but without a large load, triggering now is unlikely.

Problems

Storm Slabs

Although storm accumulations from the weekend are likely gaining strength, they may still be reactive in some wind-exposed terrain, or in areas where they overlie buried surface hoar.

Make observations and assess conditions continually as you travel.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

The deeply buried weak layers that formed in early February are still showing reactivity in snowpack tests. Possible triggers for a large destructive avalanche include cornice fall, a large force in a thin snowpack area or solar warming.

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 19th, 2014 2:00PM