Archived

Avalanche Forecast

Jan 8th, 2017–Jan 11th, 2017

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: 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.

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

Avalanche 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