Avalanche Forecast

Issued: Jan 6th, 2017 11:26AM

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

Tim Haggarty, Parks Canada

Waterton Lakes.

West winds are just squeaking past the high pressure system to the North and are building windslabs. If this continues, a fair amount of precipitation could arrive with moderate West winds... Watch for hazard to increase should this materialize.

Summary

Weather Forecast

Arctic air over much of BC and Alberta is fending off the Western push of Pacific air. Waterton is along the margin and whichever air mass wins will provide the weather over the next few days. The pacific air could spell moderate snowfall, increased winds that shift SW and then back W, as well as warming over the end of the weekend

Snowpack Summary

Yesterday, West winds began to stir up the 10-15 cm sitting around from last weekend and began forming fresh slabs along treeline ridgecrests and in lee alpine areas. In thin areas, sugary mid-pack facets continue to weaken with the sustained cold temps. The slab properties over this layer are variable and have likely lost some sensitivity as well

Avalanche Summary

A avalanche involvement reported from Glacier NP USA has lead to a fatality.Â Initial reports indicate the victim succumbed to trauma and was not buried in a slide that occurred at upper elevations. Locally only a few windslabs have been reported in the last few days but avalanches last week indicate the persistent slab problem is still of concern

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Saturday

Problems

Persistent Slabs

The weak facet layer is isolated to thin snowpack areas where the presence of any slab over these crystals would spell concern. Avoid thin snowpack areas, use caution with large uniform features, and consider the potential for shallow trigger points.

Avoid shallow snowpack areas where triggering is more likely.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Wind Slabs

Old windslabs are likely to be encountered in many areas TL and above and deserve respect, especially if they overly facets. West winds are forming fresh slabs along TL ridgecrests and in lee areas of the alpine with the snow that fell last weekend.

Be careful with wind loaded pockets while approaching and climbing ice routes.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 9th, 2017 4:00PM