Avalanche Forecast

Issued: Dec 29th, 2016 8:23AM

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

ian gale, Parks Canada

Glacier.

Moderate to heavy snowfall expected today and tonight! Limit your overhead exposure to avalanche terrain & be mindful of groups below you.

Summary

Weather Forecast

Today a trough of low pressure will bring 15-25cms of snow and 20kph SW winds at ridgetop to Roger's Pass. Friday a ridge of high pressure will set up bringing drier conditions. Another pulse of moisture could bring 5cm of new snow Saturday before the arctic high pressure settles in and we experience dry, cold conditions through next week.

Snowpack Summary

Within the last 24hrs we have received ~30cm of new snow and strong S winds that are building a reactive wind slab in the Alpine and a new storm slab at treeline and below. In recent profiles numerous failures were observed, possibly on surface hoar in the top 70 cms and this storm snow is settling into a stiffer slab.

Avalanche Summary

Yesterday skiers reported triggerable windslabs on a SW aspect at 2100m on McGill, and there were several size 2 and a size 3 natural avalanche from steep paths east of Rogers Pass. On Monday, a size 2 skier-triggered avalanche from steep, shallow, unsupported terrain carried a person over a large cliff and resulted in a rescue.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

Up to 30cm of snow fell in the last 24hrs at treeline with another 15-25 expected today & tonight. This new slab has buried a spotty surface hoar layer, that could be lurking. Expect this new load to take some time to stabilize.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes. Ski short pitches and regroup in safe spots.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

Up to 30cm of snow fell in the last 24hrs at treeline with another 15-25 expected today & tonight. This new snow combined with mod gusting strong S winds has built a fresh reactive windslab in the Alpine that has potential to propagate widely.

Watch for whumpfing, hollow sounds, and shooting cracks.Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 30th, 2016 8:00AM