Avalanche Forecast

Issued: Apr 10th, 2015 9:19AM

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

bcorrigan, Avalanche Canada

Northwest Coastal.

Safe travel will require a great deal of caution. Be aware of recent wind loading and the potential to trigger deeply buried weak layers.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

SATURDAY: Should see a slight tapering-off of precipitation during the day, with freezing levels around 800m during the day, and lowering to 500m at night. SUNDAY: Will ramp up precipitation with another 8 to 10 cm of snow at upper elevations. Freezing levels again from 500m overnight to 800m with daytime heating. MONDAY:Â Is forecast for another 5 to 10 cm of snow. Precipitation will be heavier towards the coast, but the inland portion of the Northwest Coast may see as much as 45 cm of snow at upper elevations for the period Thursday though Monday. Winds moderate to strong from the south west for the forecast period.

Avalanche Summary

No reported avalanche observations from yesterday, but commercial operators reported strong winds in the alpine stripping the new snow down to old crust surfaces and building wind slabs and sastrugi.

Snowpack Summary

New snow will be redistributed by strong south west winds into wind slabs on lee slopes. The March 25th surface hoar / crust layer may now become reactive with the new snow loading This interface has been more reactive recently in the northern part of the region, but has been reported throughout the northwest coastal area. The earlier March facet/crust persistent weakness is now down over a metre and has been producing hard, sudden planar results in snowpack tests.

Problems

Wind Slabs

Wind slabs are forming with the new snow and high winds. Use caution on lee slopes.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Additional loading on the March 25 combination layer may make this layer extremely touchy. Use caution in wind loaded areas and other deep deposition zones.

Choose conservative lines and watch for clues of instability.>Be aware of the potential for large avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Apr 11th, 2015 2:00PM