Avalanche forecast

Sea To Sky

Mar 27 – 28, 2017Avalanche Canada
View on map
Archived · expired 10 years ago

Avalanche danger

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

Highlights

Forecast new snow and wind will increase the avalanche danger. Snow fall amounts are uncertain on Tuesday; watch for developing hazard during the day.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    The forecast storm is expected to continue to develop new cornice growth. While cornices are a hazard in themselves, the danger increases when they have the potential to act as a trigger to storm slabs sitting beneath them.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    New storm slabs are expected to develop overnight and during the day on Tuesday. Precipitation amounts are uncertain; watch for developing hazard during the day.

Weather Forecast

Overnight: 5-8 cm of new snow above 1000 metres combined with moderate southwest winds. Tuesday: 10-15 cm of new snow during the day combined with strong southwest winds and freezing levels around 1300 metres. Wednesday: Another 10-15 cm of new snow combined with light to moderate southwest winds and daytime freezing levels around 1300 metres. Thursday: A brief ridge of high pressure should bring clear skies and strong solar radiation.

Avalanche Summary

Explosives control work on cornices produced some large chunks up to size 2.0 on Monday. Ski cutting also resulted in avalanches size 1.0 on Monday.

Confidence

Moderate - Freezing levels are uncertain on Tuesday

Snowpack Summary

Forecast stormy conditions are expected to add to the recent storm slabs. At about 2000 metres and below, the storm snow lies above a crust (March 22) that formed last week. Beneath this older storm snow, an older rain crust that was buried around March 15 is now about 80-100 cm deep. The mid-February crust/facet layer can still be found at the upper end of treeline and into the alpine. This interface is now generally 125-165 cm deep but may present at the surface or up to 250 cm deep in heavily wind affected terrain. Although there is growing confidence in this layer becoming dormant, continued caution is warranted while our recently formed storm slabs remain triggerable. A big enough storm slab or cornice release in the right location may have the potential to coax this layer or the shallower March 15 crust layer into reacting.

Regions covered