Avalanche forecast

Northwest Inland

Mar 11 – 12, 2015Avalanche Canada
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Archived · expired 12 years ago

Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate

Highlights

New snow and strong winds will elevate the hazard at treeline and above.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Wind slabs on a variety of old surfaces present a very real hazard at this time. Be cautious on wind affected and cross-loaded slopes

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

A Pacific low will deliver another round of moderate snowfall beginning today and continuing into next weekend. This event should bring around 30mm of precipitation, not all of which will arrive as snow ! Strong southwesterly winds will accompany the storm. Freezing levels will stay around the 1500M mark through Thursday then rise to almost 2000m on Friday before returning to more seasonal norms (valley bottom) Saturday afternoon.

Avalanche Summary

One report from yesterday of a size 2.5 natural that occurred on an East aspect around 2000m. As well, we received a report of a size 2 skier triggered avalanche on Hudsons Bay Mtn. with skier involvement and injuries. Local skiers have also reported natural activity on solar aspects. Both of these avalanches were wind slabs on old surfaces.

Snowpack Summary

Incoming precipitation will add load to the already reactive wind slabs in exposed lee terrain at treeline and in the alpine. Snow and winds from earlier in the week have added size and destructive potential to the developing wind slab problem. There are a variety of interfaces including old wind slabs, hard crusts, surface hoar, and/or surface facets buried below the recent storm snow. At the base of the snowpack, weak facets may be found and could possibly be triggered with a big enough load such as a cornice failure. Cornices are now getting to be large and potentially unstable. Solar aspects are also a concern, especially in the afternoon.

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