Avalanche Forecast
Issued: Jan 24th, 2020 4:00PM
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.
stephen holeczi,
Parks Canada
Forecasters have low confidence in the snowpack. There is lots of good skiing and climbing but picking low consequence terrain is the only way to manage the deeper layers as they are hard to predict. Large (size 3) avalanches are still possible.
Summary
Weather Forecast
Cooler daytime highs are in the forecast tomorrow. Alpine temperatures will cool to -13 by midday. Winds will also be light to moderate from the W/SW and only light flurries along the divide. Winds will pick up again for Sunday and more light snow.
Snowpack Summary
Recent wind slabs 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 (over 2m) which have basal facets but not as prevalent.
Avalanche Summary
A ginormous natural avalanche over Cascade waterfall occurred today which went on the basal facets/depth hoar. There is some speculation that the warmer temperatures may have played a factor but its anyone's guess! Some other smaller persistent slabs as well were reported in the lake Louise backcountry in the last 24 hours.
Confidence
Problems
Wind Slabs
Wind slabs exist near ridge-tops. They have been small in size but should be treated with respect, especially in gully features.
- 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 as this problem is almost impossible to forecast.
- Avoid shallow snowpack areas where triggering is more likely.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 25th, 2020 4:00PM
