Avalanche Forecast
Issued: Dec 29th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
jleblanc,
Avalanche Canada
There is a real potential for triggering larger-than-expected avalanches as slabs are sitting on a widespread weak layer.
Adopt a conservative approach by sticking to low-angle terrain.
Summary
Confidence
Moderate
Avalanche Summary
Earlier this week, a rider was accidentally caught in a large avalanche near Yanks Peak. The avalanche was triggered near a rock outcrop and most of the slope slid. Near Valemount, persistent slabs 70-100 cm deep were remotely-triggered with large explosives.
Natural avalanche occurrences are tapering off, but where avalanches did occur naturally, slabs should be expected to be primed for triggering.
Please continue to share any observations or photos on the Mountain Information Network.
Snowpack Summary
Between 30 and 60 cm of moist dense storm snow is resting on low-density weak facets grains, which gives the snowpack an upside-down feeling. This recent snow may not bond well to previous surfaces that include small surface hoar crystals, sugary faceted grains, and hard wind-packed snow.
At upper elevations, moderate to strong southerly winds have redistributed the storm snow. A very thin and breakable crust may be present at upper elevations. At lower elevations, a rain crust can be found. A buried weak layer from November lies 60 to 110 cm below the surface. Smaller avalanches may step down to this deeper layer.
The snowpack is still fairly thin and faceted, with roughly 140 to 160 cm at treeline.
Weather Summary
Quiet conditions are expected as a high-pressure system builds into the Rockies, pushing a cooler and drier air mass over the region. A wave from the Pacific will enter the Range Friday evening, with light snow and rising freezing level.
Thursday night
Mostly clear, no precipitation, southwesterly ridge winds up to 40 km/h, treeline temperatures around -12 °C.
Friday
Increasing cloudiness, light snow 3-5 cm, southwesterly ridge winds at 30 km/h, treeline temperatures -4 °C. Freezing level rising to 1000 m.
Saturday
Cloudy, light snow 3-5 cm, westerly ridge winds increasing to 45 km/, treeline temperatures around -6 °C. Freezing level around 850 m.
Sunday
Cloudy, lingering flurries, northwesterly ridge winds increasing to 45 km/, treeline temperatures around -8 °C. Freezing level dropping to valley bottom.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid rock outcroppings, convexities, and anywhere the snowpack is thin and/or variable.
- Storm slabs in motion may step down to deeply buried weak layers resulting in very large avalanches.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Problems
Storm Slabs
Storm slabs will remain reactive for longer than “typical” considering they are overlying a widespread weak layer. Human-triggered avalanches are likely where the snowpack varies from thick to thin. Watch for larger-than-expected avalanches due to the presence of a buried weak layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 30th, 2022 4:00PM
