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 Storm Slabs, Deep Persistent Slabs and Loose Wet.
lbaker,
Avalanche Canada
Updated Friday at 6:20 AM: Very dangerous avalanche conditions persist with the ongoing heavy snowfall, rain, and wind. Very large natural avalanches are possible due to buried weak layers.
Summary
Confidence
Moderate
Avalanche Summary
On Wednesday, explosives control produced several size 1 storm slab avalanches.
On Tuesday, a large storm slab avalanche was triggered by a skier on Metal Dome on an open east-facing slope at treeline. Another skier-accidental avalanche was reported to have failed within the storm snow near Oboe on a northwest slope.
Please continue to post your observations and photos to the Mountain Information Network. It helps strengthen our data gathering.
Snowpack Summary
By Friday morning, +30 cm of new snow and strong southerly winds are building reactive storm slabs in lees. New snow overlies previous wind-affected surfaces in alpine and open treeline terrain. At lower elevations, the snowpack is saturated.
A thick widespread crust formed in late December is down 60 to 90 cm. In the alpine, it is thin and breakable. Professionals are concerned that small avalanches may run down to this crust and create larger-than-expected avalanches.
Near the base of the snowpack, a weak facet/crust layer from mid-November can be found and remains a concern for triggering with large loads or on thin spots. In general, the snowpack is weak, faceted, and shallow.
Weather Summary
Thursday Night
Stormy, 30-50 mm of precipitation expected. Extreme southerly ridge winds gusting 80-100 km/h. A high of +1C at treeline. Freezing levels rise to 2000 m.
Friday
Stormy, 20-30 mm of precipitation. Extreme southerly ridge winds gusting 80-100 km/h. A high of +2C at treeline. Freezing levels hover around 1800-2000 m.
By evening the storm subsides easing winds and precip.
Saturday
Mostly cloudy with isolated flurries, 5 mm. Moderate southwesterly winds gusting 30-50 km/h. A high of -1C at treeline. freezing levels drop to 1500 m.
Sunday
A mix of sun and cloud. Light variable winds gusting 20 km/h. A high of -2C at treeline. Freezing levels continue dropping to 1200 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Use increased caution at all elevations. Storm snow is forming touchy slabs.
- If triggered, storm slabs in-motion may step down to deeper layers and result in very large avalanches.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
Problems
Storm Slabs
Forecasted snow amounts will likely develop reactive storm slabs, especially on leeward terrain features where deposits are deep. Large natural avalanches are likely, particularly where moist and heavy snow overloads the underlying dry snow.
The storm will be a test for weak layers within the snowpack. Be aware that slab avalanches could step down to a crust layer and produce larger-than-expected avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A crust with weak, faceted snow above and below exists near the base of the snowpack. The current storm could reawaken this layer and produce very large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
As rain thoroughly saturates the snowpack surface snow will lose cohesion likely resulting in a loose wet avalanche problem on steep slopes.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Jan 13th, 2023 4:00PM
