Avalanche Forecast

Issued: Feb 15th, 2014 7:12AM

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

Alberta Parks matt.mueller, Alberta Parks

If the forecast holds true we will see another natural cycle start. There is a potential for large avalanches given the amount of new snow and the overall touchy snowpack. Avoid big features and limit exposure to avalanche terrain.

Summary

Confidence

Good

Weather Forecast

Another system will roll our way over night. This new storm is predicted to bring another 40cm over the next 3 days. As usual, the alpine winds will rise to the 100km/hr+ range as the storm plays out. Ridge winds will be less, but still in the ideal range for windslab development. The westerly flow will remain a constant for the next while. The front is another warm one, we can expect daytime highs of -6.

Avalanche Summary

Numerous avalanches were noted today in alpine and treeline elevations. The majority of the avalanches appeared to come down late yesterday or last night. Sizes ranged from 1 to 2.5 and were more prevalent on NE-SE aspect. Treeline avalanches had surprisingly long propagations given the slab density.

Snowpack Summary

Significantly more wind effect in the alpine today. Crossloading was evident in most alpine gullies as were some new cornices. The alpine storm slabs have matured into windslabs that will linger for some time. The underlying surface is a volatile mix of facets and surface hoar in isolated areas. At treeline, the storm snow has settled into cohesive slabs that now have enough stiffness to propagate and be a concern. Below treeline still has a remarkably weak base with difficult trail breaking at the lower elevations. The snowpack has kept its spooky, unsupported feel. Lots of cracking and whumphing in open areas at all elevation. Snowpack confidence is low at the moment and that confidence will disappear all together as new snow is added into the mix. Snow depths are 155@Burstall Pass and 102@Burstall Parking Lot.

Problems

Storm Slabs

An icon showing Storm Slabs
If the predicted snow arrives, we can expect a short term bonding problem with the current windslab surface. Immediate lee areas will be the first place to look for the new storm slabs. Look for freshly loaded areas as you approach upper treeline.
Avoid lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

An icon showing Wind Slabs
The windslabs from the last few days will be buried and somewhat hidden. Probe the snowpack to determine if they are in your area. Unsupported rolls have been a common trigger point with the slabs.
Make observations and assess conditions continually as you travel.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Forecasters are waiting to see if this layer wakes up with the new load. So far there has been no activity on it, but if that changes look out. Large avalanches are possible with this layer.
Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Feb 16th, 2014 2:00PM