Avalanche forecast

Kootenay Boundary

Jan 17 – 18, 2013Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Strong to extreme winds out of the W/NW have left hard slabs, soft slabs, sastrugi and potentially unstable cornices in their wake. Watch for wind slabs behind midslope features like ridges and ribs. Be alert for wind slabs in unusual locations.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–5
    Slopes that didn't slide during last week's avalanche cycle are still of concern. Triggering of this layer is most likely in steep unsupported terrain. Triggering may become more likely in the afternoon on sun exposed slopes.

Confidence

Good

Weather Forecast

Friday:  Extreme W ridgetop winds at ridgetop. No precip. Potential above freezing temperatures in the alpine.Saturday:  Strong NW winds at ridgetop. No precip. Potential above freezing temperatures in the alpine.Sunday: Moderate NW winds at ridgetop.  No precip.  Potential above freezing temperatures in the alpine.

Avalanche Summary

Numerous wind slab avalanches to size 2 were reported from NE, E and SE facing slopes Wednesday.  Loose wet avalanches to size 1 were also observed on steep solar aspects.

Snowpack Summary

Recent winds have formed hard slabs, soft slabs and sastrugi in open terrain.  We've recieved reports of hard slabs up to a meter deep in the region. South and West facing slopes have been moistening up during the day with the warm temperatures.  Under the moist snow and windslabs the January 4th layer can be found down 50 - 150 cm.  It consists of small facets, surface hoar (up to 12mm) in sheltered treeline and below treeline areas, and a sun crust on steep solar aspects.  Test pits are still showing resistant planar shears at this interface, but it hasn't been reactive to human triggering for days now.The midpack is well bonded and strong.

Regions covered