Avalanche Forecast
Dec 21st, 2018–Dec 22nd, 2018
Alpine
3:
Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3:
Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2:
Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3:
Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3:
Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2:
Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3:
Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3:
Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2:
Moderate
The avalanche danger rating below treeline will be moderate
Regions: Kootenay Boundary.
A weak layer exists in our snowpack at a depth where humans can still trigger it. It is a good time to remain conservative with your terrain selection.
Confidence
High.
Weather Forecast
FRIDAY NIGHT: Clear, freezing level below valley bottom. SATURDAY: Sunny with a few clouds, moderate southwest winds, alpine temperature -9°c, freezing level below valley bottom. SUNDAY: Cloudy with light snowfall, accumulation 5cm, moderate southwest winds, alpine temperature -6°c, freezing level below valley bottom. MONDAY: Partly cloudy, light southwest winds, alpine temperature -7°c, freezing level below valley bottom.
Avalanche Summary
Large (size 2 to 3) slab avalanches were triggered naturally, by skiers, and explosives on Tuesday through Thursday. The avalanches were generally 50 to 100cm deep and either within the storm snow or on the weak layer described in the snowpack discussion. Storm slabs have stepped down to the deeper weak layer.
Snowpack Summary
Strong winds from first the south and then the northwest have redistributed the recent storm snow, producing wind slabs in lee terrain features at all elevations. Beneath this, around 50 to 100 cm of snow is poorly bonded to a rain crust and a weak layer of feathery surface hoar and sugary facets. Avalanche activity, remote triggering, and snowpack test results tell us that it is a critical layer. It is best to travel extremely cautiously with this layer in the snowpack. The lower snowpack is well-settled.
Avalanche Problems
Persistent Slabs
A weak layer buried around 50 to 100 cm is the primary concern. Expect to find it on all aspects and all elevations, except for the most exposed of terrain where wind or sun may have altered it. This weak layer has recently produced large avalanches.
Choose low-angle terrain without overhead exposure and watch for clues of instability.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3
Wind Slabs
Recent strong winds from variable directions have produced touchy wind slabs in lee terrain features. Be cautious near ridges on all aspects.
Use caution in lee areas. Recent wind loading have created wind slabs.If triggered, wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1 - 2