Avalanche Forecast

Issued: Jan 27th, 2016 8:02AM

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

chris gooliaff, Parks Canada

Glacier.

Another 10cm of snow yesterday has loaded the Jan 4 weak interface. Make good terrain decisions today, knowing this critical layer is reaching it's load limit.

Summary

Weather Forecast

Wednesday brings increasing cloud, scattered flurries, moderate SW winds at ridge-top, and freezing levels near valley bottom. As we head into Wednesday evening and Thursday, a strong system will push in, delivering moderate to heavy snowfall through Thursday afternoon. Expect 25-35cm of snow with strong SW winds and freezing levels near 1700m.

Snowpack Summary

Wind accompanied the 10cm of new snow yesterday, forming soft slabs in alpine and tree-line lee features. Below this new snow there is variable wind-effected snow in the alpine and settled, very soft slab at tree-line and below. Whumphing and cracking on the Jan 4 persistent weak layer, now buried 50-80cm, is still being reported.

Avalanche Summary

Poor visibility during the snowfall yesterday limited most observations. However, Macdonald Gully 3, a steep, planar N-facing alpine start-zone, kicked out a size 2.5 yesterday, covering most of the fan in the valley bottom. Otherwise, loose avalanches to size 1 were observed from steeper, rocky features.

Confidence

Due to the number of field observations

Problems

Persistent Slabs

The January 4th interface is buried 50-80cm deep; still within range of being triggered by a person. The incremental loading of smaller storms onto this interface makes it a tricky one to predict when/if it will fail.

Watch for signs of instability such as whumpfing, or cracking. Assess start zones carefully and use safe travel techniques.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Yesterday's snowfall with moderate SW winds has created soft slabs in the alpine and at tree-line. These hide underlying wind slabs as well. The sensitivity of these slabs is uncertain, but try to avoid lee features that have been freshly loaded.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Jan 28th, 2016 8:00AM