Avalanche Forecast

Issued: Nov 22nd, 2016 4:04PM

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

Avalanche Canada swerner, Avalanche Canada

New snow and strong winds are driving the danger ratings. With limited information on hand for this bulletin, I would tread cautiously and take the time to gather snowpack information as I go. Please submit any observations from your day to the MIN.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

The deep low off the Pacific coast remains persistent with a solid southerly flow through Friday. Cooler air accompanies this low, keeping freezing levels steady near 1000 m. Precipitation amounts are inconsistent between the models and read higher on the regional. Expecting 10-25 cm of new snow and strong winds from the southeast tonight through Wednesday. Snow amounts up to 20 cm on Thursday with moderate-strong south wind. Freezing levels will start to drop Friday as the low moves south bringing another 10-20 cm and light north winds.

Avalanche Summary

Explosive results in the alpine showed numerous cornice releases up to size 2.0. Storm slabs will continue to built and remain touchy through the stormy forecast period.

Snowpack Summary

Snow depths are variable across the region with the snow line sitting around 1400 m. Recent storm snow accumulations 25 cm plus. Strong winds combined with the new snow will likely build touchy slabs on leeward slopes and terrain features at higher elevations. Average snowpack depths at treeline are 70-120 cm with the upper 40-60 cm sitting on a thick crust and solid mid pack. In the alpine snowpack depths are 150 cm plus with the crust down 85-100 cm. Forecast strong winds and more snow will likely build touchy wind slabs on leeward slopes and terrain features at higher elevations. When traveling in the mountains Id maintain an investigative approach and dig down to test for weak layers before committing to a slope. If you've been in the mountains, please share your observations on our Mountain Information Network.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow at higher elevations are building touchy storm slabs especially on leeward slopes that see more loading due to wind transport.
Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.Make observations and assess conditions continually as you travel.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Nov 23rd, 2016 2:00PM