Avalanche Forecast
Issued: Jan 5th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Deep Persistent Slabs and Loose Dry.
tim haggarty,
Parks Canada
Avalanche Control is planned for Highway 93South and the Trans Canada Highway Monday (click links for more info) Be aware of reactive new storm and windslabs as well as the potential for avalanches on the deep persistent layer to reach run outs.
Summary
Weather Forecast
Another cold front reaches the forecast area early Sunday eventing: winds will spike again, and temperatures are forecast to drop still further to -18C in the alpine. An additional 10cm can be expected overnight before a break early Monday morning. Another warm front will approach late Monday with rising temps and increased likelihood of snow.
Snowpack Summary
20-40 cm of storm snow, strong Westerly winds and mild temperatures are promoting storm slab formation. Some of the region has a midpack which sits over facets and depth hoar at the base, and other deeper areas have a well settled snowpack with limited facets and weak layers. Digging down to see what is in the snowpack in your area is important.
Avalanche Summary
A decrease in natural activity today following a spike yesterday with strong winds. A size 3 on Mt. Field, a size 2.5 on Vermillion Peak, and another size 2.5 slide in the Sunshine area were directly observed Saturday. SSV avalanche control crews reported touchy and widespread wind slabs today particulary in N and E facing alpine terrain Sunday.
Confidence
Problems
Storm Slabs
20-40cm of storm snow has been accompanied by strong SW winds. Thick slabs in the lee of alpine and treeline features can be expected. Be on the look out in sheltered areas TL and below as this snow may be settling into a slab over surface hoar.
- Use caution in lee areas. Recent wind loading have created storm slabs.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
We have seen a few examples of these slabs becoming reactive during the storm. These large avalanches reach run out zones. As loading continues over the next few days, avoid exposure to overhead avalanche terrain.
- Avoid shallow snowpack areas where triggering is more likely.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Dry
While winds stay elevated and precipitation continues to come in, loose dry avalanches will be a problem in steep terrain. These small events can be enough to trigger a slab on slopes beneath cliffs or on ledges in gully features.
- Be very cautious with gully features.
- Use caution above ledges and cliffs where small avalanches may have severe consequences.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 6th, 2020 4:00PM
