Avalanche forecast

Northwest Coastal

Mar 10 – 11, 2012Avalanche Canada
View on map
Archived · expired 15 years ago

Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Open full map

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–6
    Recent strong winds have deposited large and reactive wind slabs in unusual places, but generally lurking below ridgecrests, behind terrain features and in gullies.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–6
    Persistent weaknesses, where they exist, may be susceptible to rider triggers. Any avalanches failing on these layers are expected to be large and destructive.

Confidence

Fair - Intensity of incoming weather is uncertain on Sunday

Weather Forecast

Sunday: light snowfall - light southerly winds - freezing level at 400m Monday: trace amounts of snow with some clearing- light southeast winds - freezing level at 400m Tuesday: very light snowfall - light southwest winds - freezing level at 200m

Avalanche Summary

A size 1.5 natural wind slab avalanche was reported on Friday on a cross-loaded slope at treeline. Storm snow avalanches up to size 3.5 were reported from the big terrain around Bear Pass. A few natural size 2 slab releases on the early February persistent weak layer interface were reported on Thursday. They occurred below treeline on steep, unsupported terrain.

Snowpack Summary

Continued strong westerly winds have created widespread reactive wind slabs on lee aspects. A persistent weak layer of surface hoar buried at the beginning of March is as much as 70cm deep and has started to become reactive in some areas. The early February persistent weak layers (surface hoar, facets, crusts) are buried as much as 110cm down and also remain a concern in some parts of the region. Although not widespread throughout the region, persistent slabs would be destructive in nature and may be reactive to human triggers, particularly below treeline on isolated and sheltered steep terrain where buried surface hoar may be preserved. Cornices in the region are reported to be large and unstable.

Regions covered