Avalanche forecast

Jasper

Mar 24 – 25, 2017Parks Canada
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Archived · expired 10 years ago

Avalanche danger

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

We are in a low probability high consequence situation. Natural activity has subsided but any slope that did not slide should be treated with utmost caution. Be vigilant if the sun comes out which could destabilize the snow rapidly.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3
    Snow is being transported at treeline and above. Slabs exist near ridge tops and open treeline spots. Avalanches to size 2.5 have been observed. Lower elevation features such as glacial moraines have slid to size 2 in isolated areas.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Large cornices on lee features with some visibly detached and looking precarious. Those that have released are triggering large avalanches from alpine terrain. Give them a wide berth.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–4
    The lower snowpack is weak with a crust from November surrounded by loose facets and depth hoar. This weakness is most developed in shallow snow with rocky terrain. A cornice failure triggered a size 3 on a NE treeline feature near Parkers ridge.

Confidence

Timing or intensity of solar radiation is uncertain

Weather Forecast

Saturday to Monday will be -3 to -12, clouds and flurries, 5cm of snow, and light to moderate SW winds. Sunday may be more sun than clouds.

Snowpack Summary

Large looming cornices are present. Wind, persistent, and deep basal slabs found at and above treeline. Mid-pack has several weaknesses yet is providing bridging strength above the weak base. Basal layer is facets and depth hoar, with a rain crust from November. On southerly slopes a melt freezing crust is developing as the pack warms.

Avalanche Summary

No patrol on Friday and nothing new reported. Thursday several fresh slab avalanches were recorded at treeline and alpine. Such as a class 3 triggered by a falling chunk of cornice on a NE facing slope, a size 2 from a S facing slope likely triggered by solar radiation, and a skier may have triggered a size 2 on a N slope near Boundary lake.

Regions covered