Avalanche forecast

South Rockies

Apr 12 – 13, 2021Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Watch for wind slabs lingering in steep open terrain and back off sun-exposed slopes as they heat up.

Avalanche problems

  • Wind Slabs

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

    As winds shift to the northeast wind slabs may be found on all aspects at upper elevations.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1.5–2.5

    Strong solar radiation and warming may trigger the large cornices that hang over ridgelines.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–1.5

    Expect natural wet loose avalanches to occur on solar aspects when the sun comes out.

Confidence

Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Weather Forecast

MONDAY NIGHT: Mostly cloudy skies, 40-60 km/h northeast wind, freezing level drops to valley bottom with treeline temperatures dropping to -10 C.

TUESDAY: Mostly sunny, 40 km/h northeast wind, freezing level to 1500 m with treeline temperatures around -3 C.

WEDNESDAY: Mostly sunny, 30 km/h northeast wind, freezing level to 2000 m with treeline temperatures around 0 C.

THURSDAY: Mostly sunny, 30 km/h northeast wind, freezing level to 2200 m with treeline temperatures reach +2 C.

Avalanche Summary

A few small dry loose avalanches were reported on Sunday. There have been some notable slab avalanches reported to the north in Kananaskis Country and Banff over the last few days, including a near miss where a skier triggered a slab avalanche on Saturday that failed on a 70 cm deep facet layer. This avalanche occurred on a north aspect at 2100 m. See the MIN report here and a follow up by Kananaskis Public Safety here. 

Warming temperatures later this week could result in slab avalanches on old weak layers, however on Tuesday temperatures will remain relatively cool with the primary concerns being wind slabs, cornices, and wet loose avalanches.

Snowpack Summary

While sunny weather is melting the surface on southerly slopes, gusty northeast wind could blow around recent snow at upper elevations and form wind slabs on lee features. Upper elevations have 15-30 cm of settling snow from recent storm, but exact amounts are variable throughout the region due to the convective nature of the spring weather. The recent snow is sitting on hard crusts on solar aspects and a mix of wind affected or soft surfaces on shady aspects. 

The mid-pack is firm and well settled. Some faceted snow and a decomposing melt-freeze crust can be found near the base of the snowpack that may become a concern later this week when things really warm up.

The snow line is creeping up to higher elevations, so some common access points are now snow free.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid lee and cross-loaded terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.

Regions covered