Avalanche Forecast

Issued: Nov 21st, 2016 8:12AM

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

ian gale, Parks Canada

Glacier.

Large Areas of Glacier National Park Are CLOSED For Avalanche Control Using EXPLOSIVES. For access information visit the Rogers Pass Discovery CentreToday is the first of the Winter Permit System (click here for more information)

Summary

Weather Forecast

2 mm of precip is expected throughout today as a weak low pressure system tracks inland and winds are forecast to 30 kph at ridgetop from the South. Warmer air associated with the incoming weather system will raise freezing levels to 1700m this afternoon. Light snow will continue through next week.

Snowpack Summary

Increasing winds and regular daily snowfall have built a storm slab in the alpine and windslab at ridgetop. The November 13 crust is buried 40-70cm and this interface is an important layer to watch as its starting to produce sudden shears in tests. Below 1900m snow depths are less than 60cm with many early season hazards.

Avalanche Summary

3 size 2.0 natural avalanches were observed from steep terrain on Mt MacDonald in the highway corridor over the last few days. A public MIN report from Saturday described a cornice triggered sz 2 running 800m from a SW asp on Video pk. Heavy sluffing was also observed on steep north facing terrain.

Confidence

Problems

Wind Slabs

Moderate South East winds have blown around the new snow at ridge top loading lee features and building new touchy soft cornices

Use caution in lee areas. Recent wind loading has created wind slabs.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Storm Slabs

Although the surface snow remains light and powdery in most places, daily new snow & warmer temps are promoting slab formation above the Nov 13 crust. Stability test have shown planar failures on this layer that indicate it is becoming more reactive

Use caution in lee areas in the alpine. Wind loading has created deeper pockets of slabs.Be cautious of sluffing in steep terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Nov 22nd, 2016 8:00AM