Avalanche forecast

South Rockies

Feb 24, 2019Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

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

Wind slabs at upper elevations remain a concern. Persistent slabs at lower elevations still have a potential for human triggering.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Winds are set to shift from southwest to east, so touchy new slabs may be expected on a variety of aspects.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5
    A weak layer of surface hoar is buried around 50 to 80 cm, which is best preserved in shaded and sheltered areas between 1600 m and 1900 m.

Confidence

High - The weather pattern is stable

Weather Forecast

SUNDAY: Sunny with cloudy periods / light east wind / alpine temperature -19MONDAY: A mix of sun and cloud / light to moderate east wind / alpine temperature -20TUESDAY: A mix of sun and cloud / light northeast wind / alpine temperature -18

Avalanche Summary

Several large (size 2) wind slabs were triggered with explosives control in the Castle area on Friday after a bout of strong to extreme southwest winds. Slab depths ranged from 20-60 cm.A MIN report from Grizzly Peak in the Elkford area on Thursday describes a persistent slab failing on the mid-January persistent weak layer as a ski touring group ascended a steeper slope near treeline. See the report here: LINK On Thursday in adjacent Waterton National Park a recent large (size 2) deep persistent slab avalanche was observed. It occurred on a steep feature below treeline that was noted for its thin snowpack and for being reverse loaded by winds.

Snowpack Summary

Wind slabs exist in open, exposed areas at higher elevations. They may be found on all aspects due to variable wind directions. A weak layer of surface hoar or faceted grains buried mid-January is 50 to 80 cm below the surface. It is found on shaded and sheltered slopes and is most prominent between 1600 m and 1900 m but has been found up to 2200 m. It may overly a melt-freeze crust on south aspects. Recent avalanche reports and snowpack test results suggest that this layer remains reactive to human triggers.The bottom half of the snowpack is composed of weak and sugary faceted snow crystals.

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