Avalanche Forecast

Issued: Dec 28th, 2016 4:02PM

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

rbuhler, Avalanche Canada

South Coast Inland.

In the south of the region, widespread storm slabs are possible and the alpine danger rating is High. In the north of the region, wind slabs are expected to be the primary concern and the alpine danger ratings is expected to Considerable.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

The last major low pressure system is expected to bring periods of heavy snowfall to the region on Thursday. 10-15 cm is expected Wednesday overnight and 20-40 cm is expected on Thursday with the deepest amounts in the south of the region. Alpine wind is forecast to be strong from the southwest on Thursday and freezing levels are expected to reach around 800 m elevation. Mostly dry and sunny conditions are expected for Friday with light alpine wind and freezing levels around 600 m. A weak storm pulse is forecast to bring around 5 cm of snow on Saturday with strong alpine wind from the northwest.

Avalanche Summary

No new avalanches have been reported from the region in several days. On Thursday, wind slab avalanches are expected throughout the region. In the south of the region, a more widespread storm slab problem is expected.

Snowpack Summary

In the Coquihalla area, around 50 cm of new snow has accumulated since Monday. In the Duffey Lake area, around 20 cm of new snow has accumulated since Monday. This new snow sits over a variable interface which consists of wind affected surfaces, faceted (sugary) snow, or surface hoar. The surface hoar has been observed up to 5 mm in size in the Duffey Lake area. A thin sun crust may also exist in the upper snowpack and was reported around Coquihalla area over the weekend. Recently strong southerly winds have formed new wind slabs in leeward and cross loaded features in wind exposed terrain. The mid and lower snowpack are generally expected to be well settled and stable.

Problems

Storm Slabs

In the deeper snowfall areas in the south of the region, a fairly widespread storm slab problem may develop on Thursday. In the north, the problem is expected to be confined to wind loaded terrain features.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 29th, 2016 2:00PM