Avalanche forecast

South Rockies

Nov 29, 2017Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Watch for wind loaded and cross loaded slopes at higher elevations.  We suspect there are weak layers near the base of the snowpack that have the potential to produce large avalanches if triggered by a wind slab release. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    Watch for signs of wind-transported, "pillowy" snow on leeward and cross-loaded slopes.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    There are several crusts now buried within the snowpack. Be extra caution in thin snowpack areas where it may be possible to trigger these layers and assume that a release near the surface may also have the potential to step-down to a deeper layer.

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

WEDNESDAY: Mainly cloudy. Moderate to strong west wind. Alpine temperature -10. Freezing level 1000 m.THURSDAY: Flurries, accumulation 5cm. Moderate west wind. Alpine temperature -10. Freezing level 1000 m.FRIDAY: Mainly cloudy. Moderate gusting to strong west wind. Alpine temperature --8. Freezing level 900 m.

Avalanche Summary

There have been no reports of avalanche activity in the region since last week's natural, wet cycle during the big rain event. To the north however, Kananaskis Country reports persistent slab activity to Size 2.5 initiating on layers at or near the base of the snowpack in the alpine and running to treeline. While natural avalanche activity has tapered off with a return to cooler temperatures and lower freezing levels, new snow and wind are creating wind slabs in alpine lee areas and the possibility of a slab release stepping down to a deeper layer within the snowpack still exists.

Snowpack Summary

As much as 10-15 cm of new snow has fallen on the most recent November rain crust at 2200 m and above while the valley bottoms saw rain. There is little information regarding snowpack structure however snowpack depths are believed to vary from 40-60 cm at 1800 m elevation, to 80-100 cm near 2300 m. Several crusts are suspected to exist within the snowpack including the most recent November crust down 10-15 cm. Below this crust lies the Halloween crust as well as the early October rain crust at the base of the snowpack.

Regions covered