Avalanche Forecast

Issued: Feb 27th, 2012 9:33AM

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

Avalanche Canada swerner, Avalanche Canada

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.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Tuesday: Mainly unsettled conditions, few flurries. Ridgetop winds 35km/hr from the South. Treeline temperatures near -10. Wednesday: Light snow amounts near 5cm. Ridgetop winds 30km/hr from the South. Treeline temperatures near -12. Thursday: Isolated flurries. Ridgetop winds 20km/hr from the West. Treeline temperatures near -8.

Avalanche Summary

Recent report of natural icefall occurred on the Loft Glacier, triggering a size 2.5 slab avalanche. Natural avalanches to size 2.0 and rider triggered to 1.5 have also been reported. Isolated areas with no wind effect, and steeper terrain features the new storm snow is sluffing.

Snowpack Summary

Up to 30 cm of new snow fell over the weekend. This adds to the previous storm snow, with 45-60 cm being an average amount over the mid February layers. Recent, intermittent 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 70cm are possible on lee features. To compound the wind slab issue, recent winds have been northerly, building reactive slabs on south facing terrain features. The mid and lower snowpack is generally well settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
Increasing winds have formed wind slabs on lee slopes and terrain features. Expect to see more widespread loading due to changing winds.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
The new snow has consolidated into a storm slab over the persistent weaknesses. Storm slabs linger as an avalanche problem in areas where they overlie buried crusts, facetted snow, old wind slabs, and/or sheltered areas with buried surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 5

Valid until: Feb 28th, 2012 8:00AM