Avalanche forecast

Purcells

Dec 31, 2013 – Jan 1, 2014Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

A number of significant avalanches have occurred in the north of this region and just beyond its northern boundary. Check the forecaster blog. Use caution if traveling in the backcountry at this time.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–4
    A weak layer buried around 50 cm from mid-December has become reactive and can be readily triggered, especially at higher elevations on a variety of aspects.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    New storm snow has been poorly bonding to the existing snowpack. Forecast new snow and winds will increase the likelihood of triggering an avalanche.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    The most likely place to trigger a deeper layer is on a steep, convex, north-facing slope in an area with a relatively shallow snowpack.

Confidence

Good

Weather Forecast

Wednesday: Dry in the morning with a chance of flurries in the afternoon. Treeline temperatures around -8C. Winds NW 30-40 km/h at ridgetop.Thursday: 5-10 cm new snow expected. Freezing levels rising briefly to around 1300 m in the afternoon. Winds W 50-60 km/h at ridgetop.Friday: 2-5 cm new snow expected. Temperatures around -10C. Winds around 30 km/h from the NW.

Avalanche Summary

A number of significant avalanches have been reported from the north of this region and just beyond its boundary to the north. One very large (size 3) avalanche was reported on Tuesday on a N aspect at 2200 m from relatively gentle terrain with a fracture depth of 100 cm. Two large (size 2) avalanches were reported from near Golden on Monday, likely triggering buried surface hoar from 10-Dec down around 50 cm. A size 3 natural avalanche was reported from the Bugaboos on Sunday on a NE aspect at 2650m, triggered by a cornice release that pulled out a large slab all the way to ground on the slope below. Outside the boundary of this region to the north of Golden, there was an incident in the Hope Creek drainage, where four people were involved (with two sustaining injuries) in a size 3 avalanche in an alpine feature on a NE aspect.

Snowpack Summary

Up to 25 cm of recent storm snow has been redistributed by moderate to strong northwest and southwest winds. These new windslabs cover older, stiff, dense wind slabs in exposed lee terrain at and above treeline. In the upper 80 cm of the snowpack a couple persistent weak layers exist, comprising of surface hoar and a facet/crust combo. This interface has produced variable results with snowpack tests, and operators are keeping a close eye on them as the load above increases and/or a slab develops.A bigger concern, especially in the Northern part of the region where the snowpack is thinner and more variable is weak faceted and depth hoar crystals combined with a crust from early October. This is now down around 80-120 cm. This deep persistent weakness appears to be more reactive in the north of the region. It is likely to be easier to trigger where the snowpack is relatively thin, and especially on steep, convex, north-facing slopes.

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