Avalanche forecast

Cariboos

Apr 10 – 11, 2013Avalanche Canada
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Archived · expired 13 years ago

Avalanche danger

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

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–6
    Recent wind and snowfall is adding to size and fragility to existing cornices. Cornice falls may be destructive by themselves, and may also trigger large avalanches on the slope below.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–6
    Moderate to heavy snowfall on Wednesday has added to an existing storm/ wind slab problem. Storm slabs may be particularly touchy in wind-affected terrain, or in spots where they overlie weak surface hoar crystals.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–4
    Rain at lower elevations has promoted ongoing wet snow instabilities. Watch for loose wet avalanches on steep slopes, or glide cracks in terrain with smooth ground cover.

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

Thursday: Light snowfall / Light northwest winds / Freezing level at 1100mFriday: Light snowfall becoming moderate in the afternoon / Strong southwest winds / Freezing level at 1100mSaturday: Light to moderate snowfall / Light southwest winds / Freezing level at 1100m

Avalanche Summary

On Monday a couple of slab avalanche to size 2.5 were remotely triggered by a skier from 300m away. The avalanches occurred on a northwest aspect in the high alpine. The early April surface hoar/ facet interface is though to be the culprit. No new avalanches were observed on Tuesday; however, observations were very limited. I would expect a new round of wind/storm slab activity in the wake of new snow and wind on Wednesday.

Snowpack Summary

At upper elevations moderate to locally heavy amounts of new snow have been shifted into deeper windslabs by steady southwest winds. About 40-75cm below the surface you are likely to find a temperature/sun crust from last week's clear weather. At the same interface you may find a touchy layer of facets or surface hoar on shaded alpine slopes above ~2400m. Where they exist these weak crystals have been responsible for large remote triggers. The variable and reactive nature of this layer suggests that it may continue to catch people by surprise. At lower elevations (below 1600m) rain has continued to saturate the snowpack. Recent snowfall and wind have made large cornices bigger and more likely to fail.

Regions covered