Avalanche Forecast

Issued: Jan 8th, 2017 4:10PM

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

jonas hoke, Parks Canada

Waterton Lakes.

Forecast snowfall amounts remain uncertain but are expected to come with warm temps and high winds, slabs will develop quickly in lees and could be surprisingly thick.

Summary

Weather Forecast

A pacific Low pressure system is pushing hard against the arctic air that persists over Alberta. Waterton is near the margin, but the pacific air should bring moderate snowfall, and increased winds Sunday night through Monday. The arctic high will re-establish itself Tuesday, giving cold clear weather through Wednesday.

Snowpack Summary

Incoming new snow will form fresh storm slabs covering previous surfaces of facetted old low density snow, and windslab in alpine areas lee to west winds. Sugary mid/lower snowpack facets have persisted due to ongoing cold temps. The slab properties over this layer are highly variable, but are most concerning in shallow snowpack areas.

Avalanche Summary

Nearby operations have reported a few small windslabs in the past couple of days. An avalanche involvement in Glacier NP USA on January 5th lead to a fatality. Reports indicate that the avalanche initiated as a soft windslab avalanche which then stepped down in to the basal facets. The victim was not buried.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

The new snow will require several days to settle and stabilize.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

Avoid thin snowpack areas, use caution with large uniform features, and consider the potential for shallow trigger points.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Wind Slabs

Windslabs that formed in immediate lees from previous West winds are now buried but may still be triggerable.

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

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Jan 11th, 2017 4:00PM