Avalanche Forecast

Issued: Dec 9th, 2012 3:00PM

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

Alberta Parks mike.koppang, Alberta Parks

Winds are increasing right now and with lots of recent snow available for transport, new slabs are quickly building.  Use caution as you transition in more wind affected areas.  Good skiing still being found in sheltered areas.

Summary

Confidence

Fair - Wind speed or direction are uncertain on Monday

Weather Forecast

Strong NW winds to continue at upper elevations over the next 36hrs.  There may be a few dribs and drabs of precipitation over the next few days but the wind will make short work of this.  Watch for wind loading on more southern aspects as opposed to just north and east over the next few days.  Temps are forecast to remain cool, unfortunately.

Avalanche Summary

One skier controlled sz 1 at 2300m on a E aspect.  15m wide, 20cm deep and ran 40m.  Evidence of a few natural avalanches up to sz 2 in the past 24hrs out of steep terrain on S and E aspects.  Fracture lines were already blow in though in locations observed.

Snowpack Summary

Skier trigger-able wind slabs up to 20cm thick building in open wind affected terrain at treeline and above with the Strong NW flow that arrived in the forecast region mid-day on sunday.  Some cracking as you transition into open areas.  Mid-pack below these new slabs is well settled with the 1106cr down 110cm but it is showing signs of breaking down. Lots of near surface facetting in below treeline areas with cold temps.

Problems

Wind Slabs

An icon showing Wind Slabs
Watch for pockets of these wind slabs along ridgelines, around cross loaded features and be especially careful in around unsupported terrain.  Small avalanches were easily ski cut on sunday but additional winds will make these slabs bigger.
Avoid unsupported slopes.>Avoid cross loaded slopes at or above treeline.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
The Nov rain crust persists about 30+cm off the ground throughout the forecast area and is reactive to stability tests in the hard range. Avalanches in the upper snowpack may step down to this weakness.
Be aware of thin areas that may propagate to deeper instabilites.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Dec 10th, 2012 2:00PM