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Avalanche Forecast

Feb 27th, 2013–Feb 28th, 2013
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Northwest Coastal.

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.

Avalanche Problems

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