Avalanche Forecast

Issued: Mar 21st, 2017 4:11PM

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

mbender, Avalanche Canada

South Coast Inland.

Snowfall amounts over the coming days vary between the north and south portions of the region. Light to moderate amounts of snow accompanied by wind gradually raise danger ratings.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Wednesday

Weather Forecast

WEDNESDAY: Flurries, accumulation 10-15cm / Moderate south wind / Alpine temperature 0 / Freezing level 1400mTHURSDAY: Flurries, accumulation 5-10cm / Moderate to strong south wind / Alpine temperature -1 / Freezing level 1300mFRIDAY: Snow, accumulation 15-30cm / Moderate south wind / Alpine temperature -1 / Freezing level 1200m

Avalanche Summary

There is no recent avalanche activity to report. On Wednesday, wind slabs may remain reactive in human triggers at upper elevations. In northern parts of the region, the deeper February weak layers continue to present a low probability / high consequence scenario.

Snowpack Summary

Expect another 10-15cm of snow at upper elevations to add to the storm snow amounts from last weekend which totalled roughly 40 cm around Coquihalla and Allison Pass and 30 cm around Duffey Lakes. Freezing levels reached roughly 1400 m at that time, resulting in rain and/or wet snow at lower elevations. Thicker wind slabs and large cornices likely exist in alpine terrain. The storm snow sits above a widespread rain crust up to about 2100 m, but the snow has likely formed a good bond to this crust. In the north of the region, the February weak layers are 80-120 cm deep and include a buried surface hoar layer that recently produced a few persistent slab avalanches and a crust/facet layer that appears to be gaining strength. In the southern parts of the region, the lower snowpack is generally stable.

Problems

Wind Slabs

Wind slabs may remain reactive at higher elevations with the wind switching from predominantly southwest to southeast

Extra caution needed around cornices with current conditions.Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Heavy triggers such as a cornice fall or a small avalanche could potentially step down to weak layers buried about 1 m deep in the northern parts of the region.

Carefully evaluate and use caution around thin snowpack areas.If triggered, wind/storm slabs may step down to deeper layers resulting in very large avalanches.Pay attention to overhead hazards like cornices which could trigger persistent slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Mar 22nd, 2017 2:00PM