Avalanche Forecast

Issued: Jan 29th, 2019 8:01AM

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

ross campbell, Parks Canada

Glacier.

Isolated Wind slabs exist up high and soft slabs at lower elevations is the story today. The next storm moving in on Friday has the potential to overload the January 17th surface hoar, resulting in a widespread cycle.

Summary

Weather Forecast

Mainly sunny today, the alpine may reach -7 on solar aspects, winds will be light from the NW, and no precipitation. Some clouds will move in tonight, flurries starting tomorrow accompanied by rising freezing levels and SW winds. A low pressure system will move over us later this week, we may see 30-40cm of new snow by Saturday.

Snowpack Summary

Extreme winds over the weekend created wind slabs on specific terrain features in the alpine and treeline. Soft slabs exist at treeline and below as the January 17th surface hoar is being incrementally buried. This layer is now buried 25-45cm, it is most reactive between 1400-1900m, and where it overlies a crust on steep solar aspects.

Avalanche Summary

Extreme winds over the weekend triggered a natural cycle in the HWY corridor to size 3, these avalanches were mainly out of extreme terrain. Reports from the back country included skier accidentals and naturals ranging in size from 1.5 to 2 at and below treeline, failing on the January 17th surface hoar.

Confidence

Due to the number and quality of field observations

Problems

Persistent Slabs

The Jan 17th Surface Hoar layer is now down 30-50cm. This layer exists on all aspects, and is most problematic between 1400-1900m on steep solar aspects where it overlies a crust.

Use caution on open slopes and convex rolls where buried surface hoar may be preserved.Convex features and steep unsupported slopes will be most prone to triggering.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

Strong to Extreme Southerly over the weekend created variable wind slabs at tree-line and above. The slab varies from soft/skiable to perfect igloo-block building crud. Expect a range of surface conditions if you go up high today.

Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.Use caution in lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 30th, 2019 8:00AM