Avalanche Forecast
Issued: Jan 10th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs, Deep Persistent Slabs and Wind Slabs.
trettie,
Avalanche Canada
Continue to make conservative terrain choices and avoid shallow rocky slopes.
In General the snowpack is weak and there is an ongoing risk of triggering a deep persistent slab.
Summary
Confidence
Moderate
Avalanche Summary
We received a report of a serious incident involving two skiers late Monday afternoon near Kaslo. The size 3 avalanche was human triggered on a west facing slope at treeline around 2100 m, failing on the deeply buried November facets. This MIN report has more details.
Although persistent/deep persistent slab avalanche activity has tapered off somewhat in recent days, reports continue to trickle in. Natural and human-triggered size 2s reported over the weekend show evidence that these layers are still reactive to human triggers and are capable of producing large avalanches.
Between the 1st and 5th of January, widespread avalanche activity was reported on persistent/deep persistent weak layers throughout the Columbias. These avalanches were naturally and human triggered, up to size 3 (very large) and failed on the weak layers described in the Snowpack Summary 70-200 cm deep. Avalanches occurred on all aspects, and mostly between 1800 and 2500 m in elevation. Check out these MIN reports from Joss Mountain, & North McCrea Mountain for an idea of the scale and features of concern.
Small slabs in wind loaded features have also been triggered by riders, which have the potential of stepping down to these deeper weak layers.
Snowpack Summary
20 to 30cm of recent snow sits over a new layer of surface hoar. Below this a well-settled upper snowpack exists. A new crust can be found at or near the surface on steep south facing terrain and low elevation terrain. Variable winds have formed wind slabs at upper elevations.
Several buried weak layers in the mid to lower snowpack continue to be a concern although avalanche activity appears to be tapering off:
A layer of crust, facets and/or surface hoar buried around Christmas sits 40-70 cm deep.
A layer of large and weak facets from mid November sits near the ground.
This year's snowpack is weaker than usual, as described in our Forecasters' blog.
Weather Summary
Tuesday Night
Cloudy with trace amounts of new snow expected. Light southerly winds and a low of -12 at 1800m.
Wednesday
Cloudy with light flurries bringing trace amounts of new snow. Light southerly winds increasing to moderate throughout the day and a high of -6 at 1800m.
Thursday
Stormy with up to 10cm of new snow expected. Strong southerly winds and a high of -4 at 1800m.
Friday
Stormy with up to 15cm of new snow expected at treeline and above. Rain at lower elevations. Freezing levels around 1600m. Moderate to strong southerly winds.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Be especially cautious as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Persistent Slabs
A layer of surface hoar, facets and/or a crust sits 40 to 70 cm deep, which is a prime depth for human triggering. This layer has been most problematic around treeline and lower alpine elevations and has produced large avalanches.
Keep terrain selection conservative in these elevation bands and practice good travel habits to reduce your exposure.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer has most recently been problematic in lower alpine elevations.
Avoid thin and rocky start zones where weak layers sit closer to the surface, riders are most likely to trigger an avalanche on this layer in terrain with shallow or variable snow depths.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Wind slabs could be found on all aspects at treeline and above.
Avalanches triggered in wind-loaded terrain have the potential to step down to deeper weak layers, creating larger than expected avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 11th, 2023 4:00PM
