Avalanche Forecast

Issued: Dec 15th, 2015 8:41AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Cornices.

jlammers, Avalanche Canada

Sea To Sky.

You don't have to be an avalanche expert to submit to the MIN. If you've been out in the mountains, we'd love to hear about what you've seen.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Mainly clear skies are forecast for Wednesday and Thursday morning. Increased cloud is expected throughout the day on Thursday with 10-30cm of new snow falling between Thursday afternoon and Friday morning. Ridgetop winds should be light to moderate from the north on Wednesday, switching to strong and southwesterly with Thursday's snowfall. Freezing levels should hover around 500m for the forecast period. For a more detailed weather overview, check-out our Mountain Weather Forecast at: avalanche.ca/weather

Avalanche Summary

On Monday there were a few reports of small loose wet avalanches running on steep, sun-exposed slopes. They occurred in response to solar radiation and brief warming. On Tuesday, we received reports of human-triggered wind slab activity to size 1 on exposed convex rolls at treeline and in the alpine.

Snowpack Summary

On Tuesday, 5-10cm of low-density snow was redistributed by winds into new wind slabs at treeline and in the alpine. These new wind slabs overlie 40-50cm of storm snow from last weekend. Limited observations suggest the recent storm snow has gained considerable strength, although I'd continue to be wary of lingering pockets of wind slab on high elevation, wind-loaded slopes. On steep, south-facing terrain you may find a sun crust from solar warming on Monday. Below 2200m, a hard rain crust can be found approximately 120cm below the surface.

Problems

Wind Slabs

On Tuesday we received reports of winds redistributing loose surface snow and forming new wind slabs in lee terrain at treeline and in the alpine. Watch for triggering in the lee of ridge crests and in gullies.

Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Recent wind and snow have formed new and potentially unstable cornices. Use extra caution when approaching ridge crests.

Stay well back from cornices.>Extra caution needed around cornices with current conditions.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 16th, 2015 2:00PM