Avalanche Forecast
Issued: Jan 23rd, 2020 4:40PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
Brian Webster,
Parks Canada
Forecasters confidence in the snow-pack is low. There is lots of good skiing but careful assessment of bigger slopes is still required. Natural avalanche activity has subsided, however human triggered avalanches are still possible.
Summary
Weather Forecast
Mixed sun and cloud for Friday with only light flurries along the divide. Freezing levels will rise to 1800 m on Friday and then return to surface for the weekend. Alpine winds will be in the moderate range out of the SW.
Snowpack Summary
Fresh wind slabs (up to size 1.5) can be found near ridge-tops. There is 40-60 cm above the Dec 31 layer of facets, surface hoar and sun crust which is slowly becoming less reactive. The bottom layer of the snow-pack consists of weak facets and depth hoar, except for deeper snow-pack areas which has a well settled lower pack.
Avalanche Summary
No new natural avalanches observed over the past few days. Explosive control Tuesday on highway 93 North produced varied results. Much of the control work produced smaller then expected results, though one large size 3.5 was triggered on the deep persistent problem.
Confidence
Problems
Wind Slabs
Fresh wind slabs exist near ridge-tops.
- Use caution in lee areas. Recent wind loading has created wind slabs.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
The late Dec layer of surface hoar, facets or sun crust is buried 40-60cm throughout the region and producing variable results depending on location and what crystal form is present. There is still high uncertainty as to how reactive this layer is.
- If triggered the persistent slab may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
In the past week we have seen several avalanches initiate or step down to this deep persistent layer. Conservative terrain choice is your best defence.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
- Avoid shallow snowpack areas where triggering is more likely.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 24th, 2020 4:00PM
