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Archived

Avalanche Forecast

Feb 27th, 2012–Feb 28th, 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
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
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.

The snowpack is tricky to predict at the moment. Backcountry travel requires local knowledge, extensive experience and training. Please read the new Forecaster's Blog Post.

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Tuesday: Mainly unsettled conditions, few flurries. Ridgetop winds 15km/hr from the South. Treeline temperatures near -9. Wednesday: Light snow amounts near 5cm. Ridgetop winds 30km/hr from the East. Treeline temperatures near -12. Thursday: Isolated flurries. Ridgetop winds 30km/hr from the SW. Treeline temperatures near -8.

Avalanche Summary

Natural ice and cornice fall has been reported. The natural ice triggered a size 2.5 on a NE aspect, while the cornice fall triggered a size 3.5 which ran to valley bottom. Reports of large loose power sluffing, entraining significant amounts of recent storm snow on N-NE aspects. West aspects also producing loose sluffing up to size 2. 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

Over the weekend new snow up to 25 cm fell. Generally, this has left us with a 45-60 cm sitting above the mid February layers. Recent clear, sunny skies have created a sun crust on south facing terrain into the alpine.The aforementioned mid February layers consist of a strong melt freeze crust below 1000m, buried wind slabs near treeline and higher into the alpine while between these elevations the interface varies wildly from facets, surface hoar, sun crust or wind press. The surface hoar seems to be spotty but is responsible for much of the recent avalanche activity. Recent testing done on the SH layers produced CTM SP down 70-100m. 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 with reverse loading.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

The persistent interface from mid February remains a concern. Large avalanches occurred on Sunday, with these layers being suspect.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 6

Loose Dry

Large, loose dry avalanches have occurred within the recent storm snow entraining significant amounts of storm snow; especially from steep terrain features mainly on N-SE aspects.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 5