Avalanche forecast

Sea To Sky

Mar 17 – 18, 2020Avalanche Canada
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Archived · expired 7 years ago

Avalanche danger

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

Watch for unstable snow on sun-exposed slopes and steep wind-affected terrain.

Avalanche problems

  • Wind Slabs

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

    Triggering wind slab avalanches remains possible after strong northeast wind formed slabs in atypical terrain features.

  • Loose Wet

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

    Sunny weather will cause wet loose avalanches on steep sun-exposed slopes. It could also weaken cornices.

Confidence

High - We have a good understanding of the snowpack structure and confidence in the weather forecast

Weather Forecast

A high pressure system brings clear dry conditions for the week.

TUESDAY NIGHT: Clear skies, light northeast wind, freezing level drops to valley bottom, alpine temperatures drop to -10 C.

WEDNESDAY: Clear skies, light north wind, freezing level climbing to 1500 m, alpine high temperatures around -2 C.

THURSDAY: Sunny with a few clouds, light south wind, freezing level climbing to 1500 m, alpine high temperatures around -2 C.

FRIDAY: Sunny, light south wind, freezing level climbing to 1500 m, alpine high temperatures around -2 C.

Avalanche Summary

On Monday warm sunny weather resulted in several wet loose avalanches on south-facing slopes in steep rocky terrain (see this MIN report for an example). Over the weekend a few size 1 human triggered wind slab avalanches were reported, and one size 2 wind slab was triggered by riders on a southwest aspect near Mt. Currie.

Looking forward, daily warming will likely cause more wet loose avalanches and potentially weaken cornices and lingering wind slabs.

Snowpack Summary

A surface crust now exists in all terrain except shaded alpine slopes. Open terrain is heavily wind affected. The snowpack is generally strong and settled, however weak faceted snow and crusts exist near the base of the snowpack in some areas, particularly the eastern and northern parts of the region. This layer is considered dormant, as it hasn't produced an avalanche since Feb 20.

Terrain and Travel

  • Back off slopes as the surface becomes moist or wet with rising temperatures.
  • Carefully evaluate steep lines for wind slabs.

Regions covered