Avalanche Forecast
Issued: Jan 3rd, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
mconlan,
Avalanche Canada
Storm and wind slabs will likely remain touchy to human traffic. The snow is loading a buried weak layer, which could produce very large and destructive avalanches.
Summary
Confidence
Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.
Weather Forecast
MONDAY NIGHT: Cloudy with snowfall, accumulation 5 to 10 cm, 30 km/h south wind, alpine temperature -13 C.
TUESDAY: Cloudy with snowfall, accumulation 10 to 20 cm, 30 km/h southwest wind, alpine temperature -12 C.
WEDNESDAY: Increasing clouds with no precipitation, 20 km/h south wind, alpine temperature -12 C.
THURSDAY: Cloudy with snowfall, accumulation 10 to 15 cm, 40 km/h southwest wind, alpine temperature -7 C.
Avalanche Summary
A natural avalanche cycle was observed within the storm snow on Sunday. It is anticipated that this natural cycle continued into Monday. Naturally-triggered avalanche activity may taper into Tuesday but the likelihood of humans triggering the storm snow remains elevated.
Snowpack Summary
Over 80 cm of snow has accumulated since the weekend, with more snow forecast into Tuesday. Storm slabs likely exist in sheltered terrain. In wind-exposed terrain, strong southerly wind during the storm has likely redistributed some of the storm snow, forming thick slabs in lee terrain features and otherwise wind-pressed snow.
The storm snow overlies a weak layer formed during the cold spell in late December. The weak layer consists of sugary faceted grains as well as potentially feathery surface hoar found in areas sheltered from the wind. In high-elevation terrain exposed to the wind, the snow likely overlies a hard wind-affected surface.
A weak layer of faceted grains may be found above a widespread melt-freeze crust that formed in early December. This layer is likely found anywhere from 100 to 250 cm deep. This layer was the culprit of large, destructive avalanches in December. It has been most reactive between 1700 and 2100 m.
The lower snowpack is well-settled and strong.
Terrain and Travel
- Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Stick to simple terrain and be aware of what is above you at all times.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Storm Slabs
Touchy storm and wind slabs have formed from the recent 80+ cm of snow. Wind slabs are likely found in wind-affected terrain from strong southerly wind and storm slabs are found in terrain sheltered from the wind. These slabs will likely remain touchy, particularly where they sit on weak snow or hard surfaces.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A weak layer of faceted grains above a hard melt-freeze crust may be found around 100 to 250 cm deep. This layer is most prominent between 1700 and 2100 m. All the recent snow is loading this weak layer, increasing the likelihood of triggering it. Humans are most likely to trigger it where it is spatially shallow, for example in thin, rocky snowpack areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 4th, 2022 4:00PM
