Avalanche Forecast
Issued: Jan 12th, 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.
trettie,
Avalanche Canada
Avoid rocky or wind loaded features where the snowpack varies from thick to thin. This is where both wind slabs and buried weak layers can most likely be triggered.
Summary
Confidence
Avalanche Summary
A couple small natural cornice failures were observed on a southwest aspect in the alpine. They triggered small wind slabs on the slopes below.
Please continue to share any observations or photos on the Mountain Information Network.
Snowpack Summary
New wind slabs will likely develop at treeline and above on west, north and east aspects throughout the day. The snow surface will likely become moist at lower elevations as the freezing level rises.
A new crust can be found at or near the surface below 1800m and on some steep south facing slopes above 1800m. A new surface hoar layer can be found down 5 to 15 on sheltered treeline features.
The two layers of greatest concern are a layer of facets, crust and surface hoar that was buried around Christmas and found around 30 to 60 cm deep. Check out this MIN for some additional info, thanks to the poster for the info! The other is a layer of large, weak facets buried in November and found near the bottom of the snowpack. This layer is likely most problematic in alpine terrain, where shallower avalanches could scrub down to these basal facets. These layers may persist for a prolonged period of time, as described in our Forecasters' blog.
Snowpack depths are roughly 100 to 175 cm at treeline. In general the snowpack is weak and shallow.
Weather Summary
Thursday Night
Cloudy with up to 5cm of new snow expected at treeline and above, rain at lower elevations. Moderate to strong southerly winds and freezing levels around 1600m.
Friday
Stormy with up to 10cm of new snow expected at treeline and above. Rain at lower elevations. Freezing levels rising to 1900m. Moderate to strong southerly winds.
Saturday
Cloudy with flurries bringing a few centimeters of new snow. Light to moderate southerly winds. Freezing level around 1600m in the south and 1000m in the north.
Sunday
Mostly cloudy with the possibility of light flurries bringing trace amounts of new snow. Light to moderate southerly winds and a high of -5 at 1800m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Wind Slabs
Watch for wind loaded terrain features from southerly winds. Back off slopes that sounds drum-like and hollow. Avalanches triggered in wind-loaded terrain could step down to deeper weak layers, creating larger than expected avalanches.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The mid and lower snowpack is generally weak, facetted and contains multiple buried weak layers. A layer of facets, surface hoar and/or crust buried 30 to 60 cm deep continues to produce test results that indicate it could be triggered by riders. Avalanches may be larger than you expect due to the depth of buried weak layers. In Shallow alpine areas it may be possible to trigger avalanches on the mid November facet layer, which is near the bottom of the snowpack.
The incoming weather will test the snowpack. Keep these layers in mind as you move through terrain. Choose terrain with low consequences.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 13th, 2023 4:00PM
