Avalanche Forecast
Issued: Jan 18th, 2024 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Persistent Slabs and Deep Persistent Slabs.
zryan,
Avalanche Canada
Recent persistent slab activity warrants conservative terrain selection.
New snow may form reactive storm slabs, in areas where a slab is not found dry loose avalanches are likely.
Summary
Confidence
Moderate
Avalanche Summary
On Wednesday, two persistent slab avalanches (size 1 and 2) were remotely triggered by skiers in the Northern Selkirks. These avalanches occurred on north aspects at treeline. Several natural and skier-triggered storm slabs were reported from alpine and treeline terrain up to size 2.
As snowfall continues on Friday, storm slab reactivity is expected to persist. Persistent slabs continue to be a concern and are best managed with conservative terrain choices.
Snowpack Summary
20 to 30 cm of low-density storm snow has buried a variety of snow surfaces. It sits above unconsolidated faceted snow, surface hoar and firm wind-pressed snow in open terrain at treeline and above.
Down 50 -70 cm, a crust, facet and or surface hoar layer exists. This may become a problem once the snow above starts to stiffen and form a slab.
130+ cm down another surface hoar layer exists that was buried in early December. This seems to be of most concern above 2000 m where a robust crust doesn't exist above it, or in shallow snowpack areas.
The depth of the snowpack varies greatly throughout the region and weak basal facets are present at the base of the snowpack.
Weather Summary
Thursday Night
Mainly clear, with cloud cover increasing in the early morning and no new snow. Alpine wind light from the southeast. Treeline temperature around -15 °C.
Friday
Cloudy with snowfall, up to 10 cm of accumulation. Alpine wind south 10 to 40 km/h. Treeline temperature rising to -10 °C.
Saturday
Cloudy with light snowfall, up to 5 cm of accumulation. Alpine wind south 10 to 30 km/h. Treeline temperature rising to -5 C.
Sunday
Cloudy with light snowfall, up to 5 cm of accumulation. Alpine wind south 10 to 30 km/h. Treeline temperature rising to -5 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Be carefull with sluffing in steep terrain, especially above cliffs and terrain traps.
Problems
Storm Slabs
Storm slabs may be touchier in wind affected terrain.
Dry loose power sluffing will likely exist in wind sheltered terrain, especially on steep slopes.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Two weak layers of surface hoar exists deeper in the snowpack. They have recently been reactive and triggered by people. As the unconsolidated snow settles and forms a slab, a reactive upper snowpack may exist.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Basal facets remain a concern in steep, rocky alpine features with thin-to-thick snowpack transitions.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Jan 19th, 2024 4:00PM
