Avalanche Forecast

Issued: Jan 28th, 2016 8:52AM

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

danyelle magnan, Parks Canada

Glacier.

Widespread natural avalanches are expected to continue today, running into the avalanche path run-outs. Conservative terrain selection, and avoiding exposure to overhead avalanche terrain is recommended.

Summary

Weather Forecast

Thursday expect another 15cm of snow, moderate to strong SW winds and freezing levels rising to 1700m. Overnight and into Friday freezing levels will drop, alpine temps are expected to lower to -8'C, and the snow will taper off. Saturday expect flurries to accumulate to another 7cm, with gusty SW winds at ridgetop.

Snowpack Summary

Up to 20 cm of new snow fell overnight, with temps just below 0 up to 1900m. The new snow is expected to settle rapidly with the mild temps into a slab. The new snow hides variable wind-effected snow in the alpine and soft slab at tree-line and below. Whumphing and cracking on the Jan 4 weak layer, now buried 50-80cm, is still being reported.

Avalanche Summary

A natural avalanche cycle is occurring as I type, with numerous size 2.5-3 avalanches occurring overnight. They occurred from all aspects, and some avalanches triggered deeper slabs at lower elevations on the avalanche fans. Yesterday numerous size 2-3 natural avalanches were triggered by windloading.

Confidence

Problems

Persistent Slabs

Incremental loading by a series of storms is making a weak layer down 50-80cm an increasing concern. This layer lingers in many areas and is sporadically reactive, making it tricky to assess. When it fails, however, large avalanches are the result.

Watch for signs of instability such as whumpfing, or cracking. Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Storm Slabs

A new storm slab is building. 30cm of snow over 48hrs at treeline, with another ~15cm forecast, is settling into a slab with mild temps. This slab may be triggered by light loads (like you) and avalanches on this layer may step down to deeper layers.

Good group management is essential to manage current conditions safely.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

The new snow hides soft windslabs in the alpine and at tree-line. Yesterday, strong winds triggered windslab avalanches. Winds are expected to increase again today, and with lots of snow available for transport the old windslabs may be overloaded.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Jan 29th, 2016 8:00AM