Avalanche forecast

Purcells

Feb 3 – 4, 2012Avalanche Canada
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Archived · expired 15 years ago

Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    You're likely to find wind slabs on N-E facing aspects, below ridgecrests and lee of terrain features.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–6
    Watch for tender cornices at ridge tops, particularly with the current warming trend. They may be destructive by themselves and they may be trigger for the slope below.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–6
    Recent avalanche activity indicates that deeply buried weak layers are once again reactive. A skier, sledder, cornice fall or avalanche running in the storm snow could trigger a large avalanche. Watch for increased activity in sun exposed terrain.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Storm slabs may be reactive to rider triggers, especially on steeper slopes and convex rolls.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Expect clear skies and light southerly winds for the entire forecast period. An inversion is also meant to dominate the region with alpine temperatures sitting at about 1.0'.

Avalanche Summary

Since the recent warming, numerous large and destructive avalanches were reported in the region. Some of these avalanches have been initiated by cornice fall. Others were loose, wet avalanches that, in some cases, stepped down to basal weaknesses.

Snowpack Summary

The big story is the recent weather. Sun exposed slopes are becoming wet and cornices are weakening due to solar radiation and increased alpine temperatures.Wind slabs are also likely to be found on exposed areas at treeline, and into the alpine and storm slabs can be found at all elevations. They both seem to be settling out quickly, but still show sensitivity to rider triggers; especially on steeper slopes and convex rolls. Below this sits a fairly well settled mid-pack. There are, however, a few exceptions. The Jan. 13th SH/FC combo has been reactive in ski hill testing. Remember this is somewhat of a modified snowpack when compared to a true backcountry uncontrolled snowpack. Regardless, I feel like we can't take our eyes off this layer just yet, remember, it's only a couple weeks old.The mid December facet/surface hoar layer is buried approx. 80 cm on the east side and 200+ cm on the west side. This layer seems to show more reactivity in the Purcells than any other region in the province and was reactive on Jan. 28th, when a skier remotely triggered a size 3 avalanche. There are basal facets at the ground which will continue to remain a concern with the current warm temperatures. Snowpack depths at 2000m sit near 2m deep.

Regions covered