Avalanche Forecast

Issued: Feb 27th, 2013 10:17AM

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

Avalanche Canada pgoddard, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period

Weather Forecast

Wednesday night/Thursday: Moderate to heavy snow (falling as rain for a time below about 900 m). Moderate to extreme SW winds. Freezing level 500 m, rising for a time to about 900m.Friday: Light snow. Moderate to strong S winds. Freezing level around 700m.Saturday: Light snow. Light winds. Freezing level dropping to valley floor.

Avalanche Summary

A few size 1 soft slabs were triggered by skiers at treeline on Tuesday.

Snowpack Summary

Strong winds created new wind slabs on a variety of slope aspects at treeline and above on Tuesday. Small surface hoar was also buried by 10-25 cm new snow. Further snowfall and wind will add to existing storm slab and wind slab problems. A rise in freezing level (aka rain) could rapidly weaken the snowpack below treeline.Old wind slabs are now buried on slopes lee to previous SW winds. Deeper in the upper snowpack, a crust, hard slab, and/or surface hoar interface exists, depending on aspect and elevation. One recent snowpack test near Shames resulted in a hard "pops" shear on the buried surface hoar, down around 60 cm at the time. Large cornices loom as a threat: they could act as triggers for avalanches on slopes below. Mid and lower snowpack layers are generally well settled and strong. The exception seems to be the Bear Pass area where basal facets are still reported.

Problems

Storm Slabs

An icon showing Storm Slabs
Snow, wind and rain (below treeline) are likely to cause a touchy storm slab problem in many areas.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Stick to simple terrain and be aware of what is above you at all times.>Give cornices a wide berth when travelling on or below ridges.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Valid until: Feb 28th, 2013 2:00PM

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