Avalanche forecast

Purcells

Dec 3 – 4, 2022Avalanche Canada
View on map
Archived · expired 4 years ago

Avalanche danger

Mon
Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map

Highlights

Snowpack is generally weak, thin, and sugary. The main avalanche hazard exists in areas where a cohesive slab has formed on top of a weak lower snowpack.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2

    Wind slabs have formed behind ribs and ridges in the alpine and treeline. These cohesive slabs likely overlay a weak, sugary lower snowpack.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–1.5

    A buried surface hoar, facet layer is beginning to become a greater hazard as snow amounts reach threshold below treeline. It will be most reactive where the upper snowpack has settled into a cohesive slab.

Confidence

Moderate

Avalanche Summary

A small (size 1) slab avalanche was observed Thursday in the upper below treeline region (~2000 m), on a steep, south-facing road bank. It failed and propagated on the sugary, faceted lower snowpack, down 25 cm from the surface.

Snowpack Summary

The surface snow continues to dry out (facet) with the current cold temperatures and is being redistributed by variable winds. In the alpine and treeline, much of the wind-exposed terrain has been scoured of snow. In deeper snowpack (loaded) areas, cohesive wind slabs may exist and generally overlie a weak, sugary, facetted lower snowpack.

The overall height of snow is highly variable throughout the region. 50-150 cm in the alpine.

Weather Summary

Friday night

Mostly cloudy with no precipitation expected, light to moderate westerly ridgetop winds, and alpine temperatures in the -15 to -20 C range.

Saturday

Clearing throughout the day. Generally light winds from the west at ridgetop, with alpine temperatures warming slightly, in the -10 to -15 C range.

Sunday

Mostly sunny, light ridgetop winds and alpine temperatures around -10 C.

Monday

Mostly sunny, light ridgetop winds and alpine temperatures around -15 C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Expect slab conditions to change drastically as you move into wind exposed terrain.
  • Carefully evaluate steep lines for wind slabs.
  • Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.

Regions covered