Avalanche forecast

South Rockies

Mar 3 – 4, 2015Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

Snow quality should be slightly improved, but be wary of touchy thin wind slabs and loose snow sluffing in steep exposed terrain.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    New snow amounts vary from only a few centimetres to around 10 cm. This snow arrived with moderate N-NE winds, which should switch to W-NW winds. Watch for pockets of wind slab on a variety of slopes in exposed terrain. 

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3–6
    Deeper weaknesses still exist and remain a concern in shallow rocky areas and anywhere the thick near-surface crust is weakening. For example, steep sunny slopes or higher north aspects.

Confidence

Fair - Due to the number of field observations

Weather Forecast

A very persistent ridge of high pressure will maintain dry and mainly sunny conditions for… a long time (at least a week, but probably longer). Temperatures should slowly rise with a freezing level near 1200-1400 m on Wednesday, 1500-1600 m on Thursday, and around 2000 m heading into the weekend. Ridge winds should be light or moderate from the NW-SW.

Avalanche Summary

No new avalanches have been reported recently but observations are limited.

Snowpack Summary

Up to 10 cm of new snow sits on the previous snow surface, which was a mix of surface hoar, crusts, wind affected surfaces, or dry powder. Periods of moderate northerly winds have produced pockets of wind slab in exposed lee terrain. The most prominent snowpack features is a thick supportive crust around 10-30 cm below the surface. It extends up to around 2200m. Below this elevation the crust is effectively capping the snowpack, preventing riders from tickling deeper persistent weak layers. In alpine areas, where the crust is not present or is less thick, it could still be possible to trigger a deep avalanche from sparsely covered rocky slopes or with a heavy load (i.e. cornice fall).

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