Avalanche Forecast
Issued: Feb 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
rgoddard,
Avalanche Canada
Variable winds may have created reactive wind slabs on all aspects at higher elevations.
The persistent slab problem is not going away any time soon. Choose terrain that has low consequences to manage this problem.
Summary
Confidence
Avalanche Summary
No new avalanche observation since the weekend. On Sunday, a size 1 wind slab was skier-triggered in a gully at treeline, reminding us that despite great riding in sheltered areas, reactive wind slabs still exist in more exposed areas. See the full report here.
A week ago, our field team observed debris from a previous large persistent slab avalanche. At least once a week evidence of large persistent slab avalanches is reported. Keep this in mind when traveling in the backcountry.
Snowpack Summary
Up to 30 cm of recent snowfall remains loose and powdery in sheltered areas. In wind-affected areas, variable winds may have created wind slabs on all aspects. This recent snow sits above a decomposing crust up to 5 cm thick that appears to be bonding well to layers above and below. This crust is widespread and found up to 1300 m and as high as 1700 m in isolated areas.
In alpine and upper treeline elevations, a weak layer of surface hoar and facets may be buried about 80 to 120 cm deep on north-to-east aspects. This layer may rest on a harder melt-freeze crust. Where preserved, this layer is capable of producing large avalanches hundreds of metres wide.
Weather Summary
Wednesday Night
Clear, no accumulation, winds northwest 45 to 50 km/h, treeline temperatures -25 ºC.
Thursday
Mostly sunny with increasing clouds in the afternoon, no accumulation, winds west 15 to 30 km/h, treeline temperatures around -20 ºC.
Friday
Cloudy, 5 cm accumulation in the early morning and another 5 cm near the end of the day, winds southwest 25 km/h ramping up to 50, treeline temperatures -20 to -15 ºC and warmer in the alpine.
Saturday
Cloudy with late day sun, 3 cm overnight and another 2 cm accumulation by the end of the day, winds southwest switching to northeast 15 to 20 km/h, treeline temperatures around -15 ºC.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- The best and safest riding will be on slopes that have soft snow without any slab properties.
- Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
Problems
Wind Slabs
Variable winds over the past few days have created wind slabs on all aspects in exposed areas. Expect the most recently formed and reactive slabs to be on south-to-west aspects from northerly winds.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
We continue to see the occasional avalanche on a weak layer of surface hoar and facets buried about 100 cm deep. Resulting in avalanches that propagated for hundreds of metres. Some of them were remotely triggered from hundreds of metres away. The common trend is that they are on north-to-east aspects around 1500 to 1700 m in elevation.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Feb 23rd, 2023 4:00PM
