Avalanche Forecast
Issued: Mar 16th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
zryan,
Avalanche Canada
Practice good travel habits and choose conservative, low consequence lines. A buried weak layer has been reactive in recent days, creating large and surprising avalanches.
Make sure to read the Avalanche Problems section.
Summary
Confidence
Weather Forecast
A series of frontal systems coming in off the coast will bring light precipitation throughout the week.
Wednesday Overnight: Mainly cloudy, light snowfall, up to 5 cm of accumulation. Freezing level dropping to 900 m. Moderate to strong southwest winds.
Thursday: Cloudy with snowfall, 5-10 cm of accumulation. Freezing level rising to 1500 m. Moderate to strong southwesterly winds.
Friday: Partially cloudy, light flurries. Freezing level rising to 1500 m in the afternoon. Light to moderate southwesterly winds.
Saturday: Mainly cloudy, light flurries. Freezing level around 1000 m. Light to moderate southwesterly winds.
Avalanche Summary
In the neighbouring Cariboos, an operator south of McBride reported a large skier-triggered avalanche that occurred on a north-facing aspect at treeline. This slab failed on a buried layer of surface hoar and propagated widely.
Explosive control on Tuesday in the Pine Pass area produced several large storm slab avalanches.
Last weekend, numerous natural and sledder-triggered avalanches were reported in the Pine Pass and Renshaw area, all failing on surface hoar. The most reactivity has occurred on wind-loaded, northeast aspects. Most notably, a size 2.5 sledder-triggered avalanche occurred near Bijoux Falls. The full report can be seen here.
Snowpack Summary
Another 5-15 cm of new snow will add to 40-70 cm of recent settling storm snow. In the alpine and treeline, southwest winds have redistributed the new snow into wind slabs in lee areas. Below treeline, moist snow or a melt-freeze crust can be expected from rain and warm temperatures.
This new snow is sitting on various surfaces, including hard wind-affected snow, sun crusts on southerly slopes, and most notably large surface hoar on shady or sheltered slopes. This layer of surface hoar is expected to remain problematic in the coming days, with the most reactivity observed in the Pine Pass and Renshaw area.
The mid and lower snowpack is generally well-settled and strong in most areas, with multiple crusts throughout. No recent persistent slab avalanches have been reported on these layers.
Terrain and Travel
- Conservative terrain selection is critical, choose only well supported, low consequence lines.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Carefully monitor the bond between the new snow and old surface.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Persistent Slabs
The most recent storm buried a weak layer of surface hoar. This layer has produced large and surprising human-triggered avalanches in the past week.
The most reactivity on this layer has been seen on wind-loaded, east-facing slopes in the alpine and treeline, but caution should be taken on all aspects as this problem unfolds. Remote-triggering is a concern. Be aware of above and adjacent slopes.
The most reactivity on this layer has been seen in the McBride corridor and Pine Pass area.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
40-70 cm of recent snow and moderate southwest winds formed fresh wind slabs in lee areas in the alpine and treeline. These slabs may be surprisingly deep and propagate widely where they are sitting on a weak layer of surface hoar or a sun crust.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 17th, 2022 4:00PM
