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Archived

Avalanche Forecast

Feb 26th, 2012–Feb 27th, 2012
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
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
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 of incoming weather is uncertain

Weather Forecast

Monday: Expect clouds to build, with snow beginning late in the day. Winds should start northerly, but turn to strong southwesterlies as the system advances. Up to 15cm are possible with daytime temps reaching -10. Tuesday & Wednesday: The storm should subside early in the day and skies will remain unsettled through Wed. Temperatures should reach -8 each afternoon under southwesterly winds.

Avalanche Summary

Many avalanches up to size 2.5 have been reported; both human and natural triggered. The smaller events released on storm interfaces while the bigger events went down to the February 09 facet/crust/surface hoar interface.

Snowpack Summary

Between 10-25cm of new snow fell in the most recent storm pulse. This adds to the previous storm snow, with 45-60 cm being an average amount over the mid February layers. Recent clear skies have created a sun crust on south facing terrain into the alpine.The mid February layers are a strong melt freeze crust at lower elevations (below 1000m) and wind effected snow higher in the alpine while between these elevations, the interface varies wildly from facets, surface hoar, sun crust or wind press. The surface hoar is not widespread but is responsible for much of the recent avalanche activity. With the additional wind loading, pockets as deep as 90cm are possible on lee features. Recent outflow winds have exacerbated the wind slab issue, building reactive slabs on south facing terrain features. The mid and lower snowpack is generally well settled and strong.

Avalanche Problems

Wind Slabs

Moderate winds and new snowfall have created new and reactive wind slabs on lee terrain. Recent outflow winds have compounded this problem.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

The persistent interface from mid February remains a concern. Slightly warmer temps have consolidated this slab.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 6