Avalanche Forecast

Issued: Jan 3rd, 2014 7:33AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs, Loose Dry and Persistent Slabs.

Alberta Parks mike.koppang, Alberta Parks

New snow, blue sky and a weak snowpack that is currently unstable.  Conservative terrain choices are a must for the next few days.  Many accidents happen immediately following a new snowfall when the sky clears. 

Summary

Confidence

Good

Weather Forecast

Cooler air is pushing into the region bringing with it cold temperatures (-15C at 2800m), light to moderate northern winds and maybe another 4-5cm of new snow overnight as the cooler air pushes out the last remaining warm air in the region. 

Avalanche Summary

Numerous loose dry sluffs up to sz 1 were observed from Alpine and treeline areas on all aspects.  There were also numerous slabs within the storm snow mainly on E and N aspects in Alpine and treeline areas up to size 2.  One noteable slide was seen on the SE face of Mt Smuts.  The entire face and some of the feeder crossloaded gullies on either side of the main path released sz 3 and ran to the valley floor.  This avalanche was up to 300m wide with fracture depths of 50cm to 200cm running 1000m. 

Snowpack Summary

25cm of new HST over the past 24hrs has fallen on the previous snow surface which consisted of stiff windslabs, facetted snow and ground.  Easy shears are being found at the HST interface but a lack of wind (in areas travelled today) prevented any slab initiation.  Deeper in the snowpack the concern is for the midpack and basal facet and depth hoar interface.  Moderate to hard result are being encountered on this layer but they are a very sudden collapse indication that when a load triggers this weakness, its likely to propogate across a feature. 

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs up to 40cm thick are being encountered in immediate lees along ridge lines and in cross loaded features. limited observations into Alpine terrain.  These slabs will QUICKLY grow when the winds increase.
Avoid freshly wind loaded features.>The new snow will require several days to settle and stabilize.>Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 4

Loose Dry

An icon showing Loose Dry
Loose dry avalanches are being observed in steeper terrain on all aspects in the Alpine and at treeline.  Some sluffs may pull out storm slabs on underlying slopes.
Avoid travelling on ledges and cliffs where sluffing may have severe consequences.>Sluffs may trigger deeper instabilities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely - Certain

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Avalanches could step down to the basal October layers and involve the entire winters snowpack, especially in shallow snowpack areas. Whumpfing has been observed in recent days.
Be aware of thin areas that may propogate to deeper instabilites.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 6

Valid until: Jan 4th, 2014 2:00PM