Avalanche Forecast
Issued: Dec 19th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
jleblanc,
Avalanche Canada
Strong outflow winds are expected to continue to affect all elevations.
Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Summary
Confidence
Avalanche Summary
Over the weekend, several wind slabs were triggered on open slopes and some were remotely triggered. The December 6th surface hoar layer, down 20-50 cm, was reported to be the failure plane. Numerous glide slabs up to size 2 were also reported in the last 48h.
If you venture into the backcountry, please consider submitting a MIN report, as it helps to strengthen our data gathering.
Snowpack Summary
Surfaces at upper elevations are highly wind-affected and variable due to switching winds. In some parts of the region, a crust exists on south aspects. Dry powder snow still exists in protected areas at lower elevations.
A layer of large surface hoar crystals, buried in early December, is found down 20 to 50 cm. This layer has been producing small but remotely-triggered avalanches recently. Reverse-loading is increasing the likelihood of triggering these slabs.
The lower snowpack is well consolidated above the mid-November crust, found at treeline below 1200 m.
Weather Summary
The same story continues with the bitterly cold arctic air mass over the region. Gusty outflow winds through the coastal inlets and extremely cold temperatures are expected to persist through Friday.
Monday night
Mainly clear. No precipitation. Northeast wind 40 km/h at ridge tops. High of -22˚C.
Tuesday
Mainly sunny. No precipitation. Northeasterly wind 30 km/h at ridge tops. High of -24˚C.
Wednesday
A mix of sun and clouds. No precipitation. Northeasterly wind 45 km/h at ridge tops. High of -24˚C.
Tuesday
Mostly cloudy. No precipitation. Northeasterly wind 20 km/h at ridge tops. High of -24˚C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be carefull around freshly wind loaded features.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
Wind slabs exist in the alpine and open areas at treeline elevations due to reverse loading created by strong outflow winds. Winds slabs could overlie a weak layer of surface hoar, facets, and/or a crust. Any avalanche in the upper snowpack has the potential to scrub down to these deeper weak layers, making for larger-than-expected avalanches. This is especially relevant at treeline elevations, where surface hoar is more likely larger and better preserved.
Aspects: South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 20th, 2022 4:00PM
