Avalanche forecast

Sea To Sky

Apr 3 – 4, 2016Avalanche Canada
View on map
Archived · expired 10 years ago

Avalanche danger

Tue
Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Open full map

Highlights

Watch for a wide range of conditions (and avalanche problems) as winter and spring weather patterns collide.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–5
    Stormy weather will encourage new cornice growth, and newly formed cornice tabs will be weak. If the sun makes an appearance, larger more destructive cornice falls will be possible.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Moderate to locally heavy snowfall and strong winds will form dense new storm slabs which will be most reactive in higher elevation, wind-exposed terrain. If the sun comes out, loose wet avalanches will become a concern on sun-exposed slopes

Confidence

Moderate - Forecast snowfall amounts are uncertain on Monday

Weather Forecast

Between 20-40mm of precipitation will fall between Sunday night and Monday. Expect a mix of sun and cloud on Tuesday and generally clear skies on Wednesday. Ridgetop winds will be strong from the southwest on Sunday night and Monday, and then remain light for the rest of the forecast period. Freezing levels are expected to sit at 2300m on Sunday night and then drop to 1400m for Monday and Tuesday. Freezing levels will then shoot back up to 2900m with Wednesday's clear weather.

Avalanche Summary

In recent days, wet slab, loose wet and cornice avalanches to size 3 were triggered naturally by warming and solar radiation. On Monday there will be a shift to more wintery avalanche problems. New snow and wind are forecast to spark a round of fresh storm slab activity in high elevation lee terrain.

Snowpack Summary

By Monday morning moderate to locally heavy amounts of snow are expected to have fallen. Due to the temperature trend in the storm (warm to cold), my feeling is the new snow will develop a reasonable bond to older surfaces which should include a mix of hard crusts on high elevation solar aspects, settled dry snow in high north-facing terrain, and moist snow everywhere else. Strong to extreme southwest winds should accompany the storm, so I would expect relatively short-lived yet potentially deep weaknesses to exist with the new snow, especially in high elevation lee terrain. The storm will also encourage ongoing cornice development and newly formed cornice tabs are expected to be sensitive to triggering. Below the new snow, the snowpack is generally strong and well-settled.

Regions covered