Avalanche Forecast

Issued: Nov 22nd, 2013 7:10AM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

We saw another avalanche cycle today involving the new wind slabs in the alpine. Both weak layers mentioned in the bulletin were involved. Rapid heating may become a trigger, especially in thin rocky areas.

Summary

Confidence

Good

Weather Forecast

High pressure is here. No new snow for the next few days, just sun. The temps are expected to rise to above zero in valley bottoms and hover just below zero in the treeline range. Winds will stay at the moderate level with the occasional bump to strong.

Avalanche Summary

A widespread Na cycle started today involving the new storm slabs. Slides up to 2.5 were noted throughout the forecast area. They all initiated in the alpine with a variety of layers suspected as the sliding layer. A sun triggered sz2 pulled out on Rundle with the Oct temp crust being the culprit.Â Storm snow/existing wind slab interfaces are suspected in the others. The avalanches were in moderately angled terrain (35-45 degrees) and tended to be in more open areas. N-SE aspects.

Snowpack Summary

Wind slabs created with the readily available storm snow continue to develop (and shed) in the alpine. A fairly widespread cycle was observed today with lots of activity in the alpine. Most alpine features had evidence of slab avalanches from the last 12 hours. At TL & below the snowpack is still weak with difficult trail breaking up to TL. The ongoing crust problem is still there and a real concern in thinner areas.

Problems

Storm Slabs

These delayed storm slabs have become reactive to natural triggers in the last 24 hours. The windloading has been ongoing for a number of days and the sliding layer now has enough load to be reactive. Human triggering is a real possibility.

Avoid areas with overhead hazard.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

The wind slabs that are sandwiched between the crust and storm slabs are still a concern. Stepping down may become a concern as load increases, as are thin areas where the crust is easier to disturb.

Carefully evaluate and use caution around thin snowpack areas.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Valid until: Nov 23rd, 2013 2:00PM