Avalanche forecast

South Columbia

Apr 19 – 20, 2017Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Forecast snowfall amounts for Thursday may vary greatly due to the convective nature of the weather system passing through.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Convective flurries and moderate southwesterly winds may create small wind slabs in the lee of terrain features.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    The likelihood of cornices triggering increases with intense sunshine and/or during the warmest parts of the day.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

THURSDAY: Cloudy with isolated flurries / Light west wind / Alpine temperature -1 / Freezing level 1700mFRIDAY: Mix of sun and cloud / Light to moderate northwest wind / Alpine temperature 0 / Freezing level 1900mSATURDAY: Cloudy with sunny periods / Light south wind / Alpine temperature 2 / Freezing level 2200mNOTE: Convective flurries, which are common this time of year, can result in widely varying snowfall amounts. These spring squalls routinely drop 20+ cm of snow in one valley while the adjacent drainage remains dry. For this reason, the distribution of avalanche problems associated with new snow vary greatly within a region.

Avalanche Summary

Recent reports indicate natural loose wet activity to size 1.5 and 2.5 in the alpine and tree line elevation bands on all aspects except north. Additionally a few wet slab avalanches to size 2.5 have been observed at tree line on southerly aspects. Exposure to large overhanging cornices remains a significant concern.

Snowpack Summary

Recent new snow tree line and above has been redistributed by west and south winds. The middle of the snowpack is generally well settled and continues to transition into a spring melt/freeze regime except for high elevation northerly aspects. Expect the entire thickness of the snowpack to be moist or wet at lower elevations. At upper elevations a deep persistent layer consisting of facets sitting on a crust that was buried back in November has been sporadically reactive to heavy loads i.e. a cornice fall or the weight of a smaller avalanche running. Cornices remain large and continue to become more overhanging.

Regions covered