Avalanche forecast

Purcells

Mar 9 – 10, 2015Avalanche Canada
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Archived · expired 12 years ago

Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low

Highlights

Forecast warm temperatures, sunny skies, and high freezing levels are expected to weaken windslabs and cornices in the alpine.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Changing wind directions continue to develop new windslabs in the alpine.
  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Forecast warm temperatures and high freezing levels may weaken cornices.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Mix of high cloud and clear skies overnight with moderate southwest winds and freezing levels dropping down to about 1200 metres. Some warm air (slightly below freezing) may remain at higher elevations overnight. Tuesday mostly sunny with a chance of high cloud combined with light southwest winds and freezing levels rising up to about 2100 metres. Cloudy with light precipitation on Wednesday with moderate southwest winds and freezing levels around 1800 metres. Mix of sun and cloud on Thursday with light winds and 1600 metre freezing levels.

Avalanche Summary

Several cornice falls up to size 2.5 were reported on Monday. Continued strong westerly winds are developing windslabs on lee aspects.

Snowpack Summary

Roughly 5-10 cm of recent snow adds to the variable amounts of dry facetted snow on top of the mid-February crust with associated buried surface hoar in sheltered areas, or, more recent melt-freeze crusts on sun-exposed slopes. The late-Jan crust/surface hoar layer can be found about a metre below the surface in deeper snowpack areas. The mid-January surface hoar, can be found below that. These layers have gained significant strength, and chances of triggering these weaknesses have decreased dramatically. However, triggering may be possible with a large input such as cornice fall, or an avalanche stepping down, especially on slopes that see a lot of sun.

Regions covered