Avalanche forecast

Jasper

Apr 10 – 11, 2014Parks Canada
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Archived · expired 12 years ago

Avalanche danger

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

Afternoon warming and solar radiation can rapidly increase the avalanche danger at all elevations.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Strong to extreme southerly winds continue to form slabs dating from early April. Slab activity stepping to ground quickly. Buried sun crust can present a sliding layer as seen at 2300m near Marmot. Sheltered snow can be found at treeline and below.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Cool temperatures are suppressing this building instability. Localized sunny breaks will quickly reverse this big picture qualifier rapidly increasing the danger on the local radiated slope. Snowballing and pinwheels are good warning signs.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–3
    Most observed avalanches in the past week are stepping down to this layer. Frequently observed between 2200-2400m and triggered by  wind loading, cornice falls of solar exposure. Most common in shallow areas or near rock outcrops.

Weather Forecast

A continued Westerly flow with snow flurries at high elevations. Daytime freezing levels will remain below treeline on Friday and Saturday. Clearing skies and sunshine are forecast for Sunday and into the new week ahead.

Snowpack Summary

At treeline (TL) and below warming temperatures are destabilizing the snowpack. Moist snow in the upper pack can be anticipated. Surface crusts will form overnight when temps drop. Solar facing slopes close to TL may have buried crusts with slab snow above. Deeply buried weaknesses near ground are a concern as are windslabs at and above TL.

Avalanche Summary

Slab avalanches observed Tuesday and Wednesday up to size 2.5 from treeline (TL) and the low alpine. All events are stepping to ground. Most are being triggered by wind loading or cornice failure. Strong SW winds are developing wind slabs. Afternoon warming and solar radiation is producing point and wet slab releases from below treeline.

Confidence

Freezing levels are uncertain on Friday

Regions covered