Avalanche Forecast

Issued: Feb 16th, 2013 8:26AM

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

Parks Canada danyelle magnan, Parks Canada

A storm passing through the region today may be more intense than expected. Avalanche danger may rise to High during periods of heavy snowfall and/or high winds. Avoid exposure to avalanche terrain if winds increase or it really starts dumping snow.

Summary

Weather Forecast

Avalanche danger will increase today. As a cold front passes through the region winds will increase and steady snow may add up to 20cm of snow by Sunday morning. Precipitation should taper off by Sunday afternoon with possible sunny periods.  Monday should be mostly sunny, with cool alpine temperatures and moderate SW'ly winds.

Snowpack Summary

Soft slabs are most cohesive above treeline; a result of southerly winds. A widespread surface hoar layer down 25-40cm is most reactive where it is largest; between 1700-1900m; or on steep solar aspects where it formed over a sun crust. A series of surface hoar and crust layers up to 1m below this layer continue to fail in snowpack tests.

Avalanche Summary

There have been several reports of skiers accidentally triggering avalanches up to size 2 on the most recent surface hoar layer. These have occurred on all aspects and elevations, with the avalanches propagating up to 80m wide and traveling fast and far. Skiers in these areas have reported clues such as cracks shooting up to 80m from their ski tips

Confidence

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

Problems

Persistent Slabs

An icon showing Persistent Slabs
A touchy surface hoar layer is down 25-40cm. There have been human triggered avalanches on this layer daily. Avalanches are increasingly possible with new snow and rising winds today adding load, and mild temperatures making the slab more cohesive.
Good day to make conservative terrain choices.Good group management is essential to manage current conditions safely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

An icon showing Wind Slabs
Soft windslabs formed on lee slopes above treeline last week from southerly winds. In wind-affected areas the recent storm snow will be more cohesive. These slabs overlay a touchy surface hoar layer and if triggered, avalanches may propagate widely.
Be cautious as you transition into wind affected terrain.Choose well supported terrain without convexities.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Feb 17th, 2013 8:00AM