Avalanche Forecast

Issued: Jan 23rd, 2016 7:30AM

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

Avalanche Canada pmarshall, Avalanche Canada

We should see a couple relatively calm days between storm cycles.

Summary

Confidence

High

Weather Forecast

Sunday: Cloudy with sunny breaks and a chance of flurries. The freezing level is around 800-1000 m and winds are light from the S-SW. Monday: Cloudy with sunny breaks. The freezing level remains near 1000-1200 m and winds are light from the S-SW. Tuesday: Cloudy with moderate snow/rain. The freezing level rises to 1800-2000 m and winds increase to moderate from the S-SW.

Avalanche Summary

Widespread natural slab and loose wet activity up to size 3 was reported on Friday. Activity was observed on all aspects and at all elevations; however, alpine observations were limited due to poor visibility. Cooling temperatures and drier conditions this weekend will help stabilize the snowpack and reduce the likelihood of triggering slab avalanches.

Snowpack Summary

The "Pineapple Express Light" dumped 80-160 mm of precipitation on the South Coast this week. Most of this fell as snow above 1800-2000 m (over 1 m) with mixed rain and snow or just heavy rain below 1800 m. Heavy snow and strong winds have formed deep and dense wind slabs in exposed lee terrain and caused substantial cornice growth. Expect to find a rain crust at or near the surface (below 10-20 cm of fresh snow) at lower elevations. The early and mid-January surface hoar layers may have been wiped out by the storm and subsequent avalanche cycle. These layers would be down between 100 and 150 cm deep now. Tread cautiously until we know more about the state of these persistent weaknesses. The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted.

Problems

Storm Slabs

An icon showing Storm Slabs
Fresh storm slabs have probably settled and strengthened significantly but watch for triggering in steep unsupported terrain, especially exposed wind-loaded slopes. 
Choose well supported terrain without convexities.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Cornices

An icon showing Cornices
Cornices are becoming large and may fail naturally or under the weight of a person or snowmobile. 
Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Two layers of buried surface hoar could still be found down 100-150 cm deep. Triggering may still be possible with heavy loads in specific features (slopes near treeline that did not previously slide).
Be wary of slopes that did not previously avalanche - even on low angle terrain.>Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Jan 24th, 2016 2:00PM