Avalanche forecast

Jasper

Mar 22 – 23, 2013Parks Canada
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Archived · expired 14 years ago

Avalanche danger

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

Cornices are large and looming. Give them a wide berth as their failure has the potential to trigger deep instabilities. Trigger ability increases with daytime heating and sun.

Avalanche problems

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    The 90cm of snow since March 13 has generally melded with the snowpack making for a deep persistent slab. North and South winds have this present on a variety of aspects overlying weak basal facets. Cornice failures can trigger this in a big way.

Weather Forecast

The weekend will have flurries, clouds intermixed with sun, diurnal fluctuation of cold nights and freezing level 1000m or higher by the afternoon, and calm to light North winds. Monday and later will have sunny conditions, freezing level 1500m or higher, and trending increasingly warmer each afternoon.

Snowpack Summary

The surface storm and wind slab have melded with the snowpack making a persistent slab in alpine and treeline locations on a variety of aspects. 90cm has fallen since March 13 and was moved around by variable winds since then. At treeline in south facing terrain, the snow rests on a suncrust 80 cm deep. The snowpack is generally supportive.

Avalanche Summary

A size 3 triggered by cornice failure in the afternoon heat, scrubbed to ground, 2m crown, and ran full path occurred yesterday in the Shangrila area. A helicopter flight Tuesday revealed a significant avalanche cycle occurred on N to NE alpine slopes to size 3 and on terrain as low as 25 degrees triggered by wind loading and sunny skies. 

Confidence

Timing or intensity of solar radiation is uncertain

Regions covered