Avalanche forecast

Sea To Sky

Mar 21 – 22, 2016Avalanche Canada
View on map
Archived · expired 11 years ago

Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map

Highlights

Conditions may change quickly in the spring. Even brief periods of sun can trigger pushy loose wet avalanches or promote destructive cornice falls.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    New snow accumulations from Sunday night are expected to strengthen rather quickly. That said, new wind slabs may remain sensitive to human triggering in high elevation, wind-exposed terrain.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–5
    Some cornices are larger than a bus, and could easily collapse under the weight of a person or with daytime warming. Give these monsters a wide berth when traveling on or below ridge crests.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Brief periods of solar radiation are possible on Tuesday. If this happens, pushy loose wet avalanches will become a concern in sun-exposed terrain.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Tuesday

Weather Forecast

On Tuesday expect generally overcast skies with isolated flurries. On Wednesday a Pacific system will bring 10-20cm of new snow to the region. Light flurries are forecast for Thursday. Ridgetop winds will be light on Tuesday, and then become moderate and southwesterly with Wednesday's precipitation. Freezing levels should hover between 1200 and 1300m for the forecast period.

Avalanche Summary

On Friday, there was an anomalous size 2.5 slab avalanche on an unsupported rocky face on the northwest corner of Mt Fissile (in the Fitzsimmons Range) at about 1900m. Although the sliding layer is unknown, the avalanche was thought to have been triggered by warming. Over the past week there have also been numerous reports of solar-triggered cornice falls. Some cornice falls have been large (up to size 3), but most have only entrained surface snow. Explosives control ion Monday triggered storm slabs and cornice falls to size 2 in mostly alpine terrain.

Snowpack Summary

On Sunday night the region received between 12 and 30cm of new snow with highest amounts falling in the Southern Garibaldi/ Brandywine parts of the region. Moderate southerly winds formed soft slabs which seemed most reactive in lee alpine terrain. The new snow overlies a sun crust on sun-exposed slopes, dry settled powder on shady slopes and moist snow below 1800m. Below the new snow the snowpack is strong and well-settled throughout with no notable persistent weaknesses. Cornices are huge and fragile.

Regions covered