Avalanche forecast

South Rockies

Jan 18 – 19, 2014Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Daytime heating and solar radiation will play a large role in the danger rating for the next few days.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Strong winds have created hard wind slabs in the alpine and at tree line, very warm temperatures and strong solar radiation may increase the likelihood of triggering. A cornice failure or radiation sloughing in cliffs may trigger lower slopes.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Cornices may become weak and fall off naturally due to strong solar radiation and forecast warm alpine temperatures. Cornice falls are a large load that may release buried persistent weak layers on slopes below, resulting in very large avalanches.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–6
    Recent storm snow and hard wind slabs have been added to the load above buried weak layers. Deeply buried weak layers may become harder to trigger, but the consequences are very large destructive avalanches.

Confidence

Good - Timing or intensity of solar radiation is uncertain

Weather Forecast

Overnight: Temperatures cooling down, nil precip., freezing level at valley bottom, light to moderate SW winds.Sunday: Sunny with some cloudy periods, nil precip., variable light winds. Freezing level around 900m.Monday: Sunny with some cloudy periods, nil precip., light winds, freezing level at valley bottom.Tuesday: Sunny with some cloudy periods, nil precip., light winds, freezing levels rise to around 1300m.

Avalanche Summary

1 size 2.5 snowmobile triggered avalanche in steep shallow snowpack, failing to near ground level. Areas of shallow snowpack are of special concern, as well as areas where there is a hazard from above such as cornices or steep south facing cliffs.

Snowpack Summary

Extensive wind transport and wind slab development has occurred in all areas of the region. Recent storm snow varies from 40-70 cm across the region and in some alpine areas storm slabs are more than a metre thick. Persistent weak layers of buried crusts/facets/surface hoar continue to be a concern, and may have been the failure plane for recent large natural avalanches. Forecast very warm temperatures may result in loose wet avalanches or cornice falls that may trigger the persistent weak layer at the base of the snow pack ( depth hoar ). Strong solar radiation combined with above freezing temperatures in the alpine could create very touchy triggering on Southerly aspects.

Regions covered