Avalanche Forecast

Issued: Jan 21st, 2016 3:00PM

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

Alberta Parks mike.koppang, Alberta Parks

Warm temps and strong sw winds combined with new snow are creating ideal conditions for slab development.  Heads up as you move into more wind affected areas.  The times of "Given er" are at an end for a while...

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Friday

Weather Forecast

Warm temps and strong southwest winds are expected to continue overnight.  Forecast models are currently calling for 7cm overnight and another 5cm of snow throughout the day on Friday.  Freezing level on friday is forecast to be around 1900m.

Avalanche Summary

Forecaster were able to easily trigger a few smaller sz 1 avalanches on wind loaded features at TL in the Burstall Pass area.  These slabs were failing down 20-30cm on the Jan 6th Infterface.  A few sz 1.5 slabs were also observed along ridgelines on N and E aspects in Alpine areas that entrained the loose dry facets on the lower slopes running far. 

Snowpack Summary

Up to 25cm of snow is now overlying the Jan 6th Facet/Surface hoar interface.  Cracking was apparent in open wind affected terrain while travelling in treeline features today indicating that this layer is within the range of human triggerring.  Where the snow is more wind affected triggerring will be easier.  There was no cracking observed below treeline.  Strong winds and warm temps are rapidly building new persistent slabs on this interface.  Skiers will need to pay attention as the transition into open wind affected areas.  Another 10cm of snow is expected to fall overnight under the influence of strong temps so its unlikely stability it likely to improve before the weekend.

Problems

Persistent Slabs

An icon showing Persistent Slabs
New Persistent slabs up to 30cm thick are developing. May be deeper along ridgelines and specific lee features.
Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>Avoid unsupported slopes.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Wind Slabs

An icon showing Wind Slabs
In areas where this new snow is overlying the previous hard surface slides may be more easily triggerred.
Avoid lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Jan 22nd, 2016 2:00PM