Avalanche Forecast
Issued: Jan 4th, 2020 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
Stormy conditions continue this weekend. Both natural and human-triggered avalanches are very likely, with the potential for very large avalanches to reach the valley bottom. Travel in avalanche terrain is not recommended, including travel in runout zones.
Summary
Confidence
Weather Forecast
SATURDAY NIGHT: Cloudy with snowfall, accumulation 20 to 30 cm, moderate to strong southwest wind, alpine temperature -9 C, freezing level 800 m.
SUNDAY: Cloudy with snowfall, accumulation 20 to 40 cm, strong southwest wind, alpine temperature -7 C, freezing level 1000 m.
MONDAY: Cloudy with snowfall, accumulation 10 to 20 cm, moderate southwest wind, alpine temperature -7 C, freezing level 800 m.
TUESDAY: Cloudy with snowfall, accumulation 30 to 50 cm, moderate to strong southwest wind, alpine temperature -3 C, freezing level 1100 m.
Avalanche Summary
On Saturday, a large avalanche released on the weak layer described in the snowpack summary. The avalanche occurred in alpine terrain and had a slab thickness of 150 cm.
On Friday, many small storm slab avalanches were triggered naturally, by humans, and by explosives.
Avalanche activity is expected to continue into Sunday as more snow accumulates.
Snowpack Summary
Intense snowfall continues in the region, forming dangerous avalanche conditions. Snowfall amounts may reach 40 to 60 cm Saturday night into Sunday, adding to the 30 to 70 cm from Friday. All of this snow is falling with strong southwest wind, redistributing it in exposed alpine and treeline areas. The snow may overly a touchy weak layer of feathery surface hoar, making storm slabs particularly touchy.
Near the bottom of the snowpack around 150 to 200 cm deep, sugary faceted grains and a hard melt-freeze crust exist from mid-November, which is an indicative snowpack setup for large and destructive avalanches. The likelihood of natural and human-triggered avalanches on this layer remains elevated with the rapid loading occurring during this stormy period.
Terrain and Travel
- Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
- Avoid the runout zones of avalanche paths. Avalanches could run full path.
Problems
Storm Slabs
Intense stormy conditions continue, with another 40 to 60 cm of snow possible Saturday night into Sunday for much of the region. The snow will fall with strong southwest wind, loading lee terrain features. Touchy storm slabs will be reactive to both human and natural triggers on Sunday. Travel in avalanche terrain is not recommended.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A touchy weak layer is buried near the bottom of the snowpack. This layer has been responsible for many large, destructive avalanches in the region. The consequence of triggering this layer would be severe. The likelihood of triggering this layer will be elevated during the stormy conditions on Sunday.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 5th, 2020 5:00PM
