Avalanche Forecast

Issued: Apr 13th, 2015 9:22AM

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

swerner, Avalanche Canada

Northwest Inland.

Localized solar radiation, snow amounts and wind values may be higher than forecast. Use a conservative approach and watch for signs of instabilities like natural avalanche activity.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Winter continues in the North as another intense storm moves onto the coast tonight resulting in very strong winds and light precipitation amounts. Very unstable air will result in unsettled conditions on Tuesday where localized light-moderate precipitation is possible ( 5-15 mm) accompanied by strong west winds and freezing levels near 1200 m. On Wednesday, precipitation amounts could see up to another 10 mm, freezing levels and winds consistent with Tuesday. There will be a lull in the weather pattern Thursday before things redevelop on Friday as another storm tracks across northern BC.

Avalanche Summary

No reports of natural avalanche activity yesterday. With continued precipitation, localized solar radiation and strong winds new storm slabs and winds slabs will likely be touchy on Tuesday. Natural and human triggered avalanches up to size 2 are expected.

Snowpack Summary

What new snow we have received has been blown into wind slabs on exposed lee slopes. The main concerns right now are wind slabs over a variety of surfaces that include crusts, facets and surface hoar that formed in in sheltered places during the last spell of clear cool weather. Large ripe cornices are also of concern and will be a problem with additional loading, especially when the sun and warm temperatures come back. The March 25th crust with facets appears to be inactive, but is worthkeeping on the radar with forecast snow and wind.

Problems

Wind Slabs

Strong winds have built wind slabs in lee terrain in the alpine and at treeline. They are especially touchy where they sit on buried facets, surface hoar and/ or crusts. Use caution and watch for reverse loaded slopes from changing winds.

Be cautious as you transition into wind affected terrain.>Pay attention to overhead hazards like cornices.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

Additional snow loading on the mid- March persistent weak layer could bring it back to life. Smaller storm slab avalanches may step down to this layer, initiating large and destructive avalanches.

Dig down to find and test weak layers before committing to a line.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar, facets and/ or a crust.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Apr 14th, 2015 2:00PM