Avalanche Forecast
Issued: Jan 28th, 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.
aaron beardmore,
Parks Canada
Extreme wind on Wednesday will load lee areas and create wind-slabs. A storm is set to arrive on Friday, raising the avalanche hazard when the snow arrives.
Summary
Weather Forecast
Increasing wind from the SW will start early on Wednesday, loading alpine lee areas. Temperatures will be very similar to the last few days. The leading edge of a major front is expected to deliver snow starting in the early morning hours on Friday.
Snowpack Summary
There is 40-80 cm above the Dec 31 layer of facets, surface hoar and sun crust which produces test results in the hard range. The bottom layer of the snow-pack consists of weak facets and depth hoar, except for in deeper snow-pack areas (over 2m) where the basal facets are not as prominent.
Avalanche Summary
No avalanches observed or reported on Tuesday.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Friday
Problems
Wind Slabs
Extreme wind values from the SW throughout the day on Wednesday will load lee areas, especially in the alpine. Due to the extreme winds, wind slabs could be forming at tree line.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The late December layer of surface hoar, facets or sun crust is buried 40-80cm throughout the region and produces typically hard results. Be suspicious on steep solar aspects and look for surface hoar.
- If triggered the persistent slab may step down to deeper layers resulting in large avalanches.
- Dig down to find and test weak layers before committing to a piece of terrain.
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 of facets, depth hoar and crusts. Be cautious with shallow snowpack areas and avoid thin spots.
- 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 29th, 2020 4:00PM
