Avalanche Forecast

Issued: Jan 8th, 2015 7:38AM

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

Peter, Avalanche Canada

South Rockies.

Recent wind and warming have probably resulted in variable conditions throughout the region.

Summary

Confidence

Fair - The weather pattern is stable

Weather Forecast

Synopsis: A strong ridge of pressure will dominate the weather pattern for at least the next few days. Expect a mix of sun and cloud, light or moderate W-NW winds, and slight temperature inversion (although staying below zero). The only blip on the horizon is late Saturday/Sunday when a weak trough slides across the province. This might result in more cloud and a chance of flurries but no significant accumulations.

Avalanche Summary

One observer north of Sparwood reported one natural size 1.5 slab avalanche and one remotely triggered size 2 avalanche on Wednesday, both sliding on the buried crust layer down 30-50 cm. On Tuesday, there was one report of a size 2.5 natural slab avalanche from Allison Peak in the Crowsnest Pass.

Snowpack Summary

Below treeline and on south-facing slopes there may be a melt-freeze crust overlying up to 20 cm of recent snow. At higher elevations the new snow has been blown into wind slabs in exposed lee terrain. The recent snow sits on hard wind slabs in exposed terrain, and low density faceted snow in sheltered areas. Up to 75 cm below the surface you will likely find a hard, thick crust which formed mid-December. This crust has overlying facets and surface hoar (up to 10 mm in sheltered locations at treeline and below). This layer seems variably reactive throughout the region. In areas where the overlying slab is thick and cohesive, large avalanches are possible at this interface. A crust/facet combo which formed in November seems to have gone dormant for the time being.

Problems

Wind Slabs

Moderate to strong winds may have created fresh and potentially reactive wind slabs in exposed lee terrain. Watch for triggering in the lee of ridge crests and terrain breaks.

Be cautious as you transition into wind affected terrain.>Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

A buried persistent weakness down 30-50 cm should remain on your radar as it has the potential to produce large avalanches. Dig down and test weak layers before committing to a line.

Avoid convexities or areas with a thin or variable snowpack where triggering could be more likely.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Jan 9th, 2015 2:00PM