Avalanche forecast

Northwest Inland

Apr 5 – 6, 2012Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    Thin wind slabs have formed in exposed lee and cross-loaded features. Watch for triggering in gullies, behind ridge crests and over rolls in terrain.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Large cornices exist in alpine terrain and they may pop off with warmer temperatures and intense solar radiation. A failure could be destructive by itself, and could also trigger an avalanche on the slope below.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Loose wet avalanches are likely on sun exposed slopes during the day. Isolated wet slab avalanches are also possible.

Confidence

Good

Weather Forecast

A ridge of high pressure is expected to keep the northwest ranges mainly sunny and dry with light winds throughout the forecast period. Freezing levels are expected to reach 1500m during the day, but drop back down to valley bottoms at night.

Avalanche Summary

Reports from Wednesday include some larger wet sluffs from steep rocky sun-exposed terrain. Cornices have also been failing over the past couple of days, some of which triggered wind slab avalanches up to Size 2 on the slope below.

Snowpack Summary

Moderate winds have blown light amounts of new snow into variable wind slabs in exposed lee and cross-loaded terrain, which are starting to bond. Surface snow on sun-exposed slopes is undergoing a daily melt-freeze cycle. In sheltered areas 15-30cm of new snow sits on the previous surface that includes crusts (found on all aspects below 1000m and on solar aspects higher up), and old wind slabs. Not only will daytime warming and sun-exposure cause surface snow to lose cohesion and cornices to weaken, they will also increase settlement rates and decrease slab stability.

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