Avalanche Forecast
Issued: Feb 5th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
shorton,
Avalanche Canada
Triggering large avalanches remains a concern as we leave a period of stormy weather.
Summary
Confidence
Weather Forecast
WEDNESDAY NIGHT: Cloudy with isolated flurries and trace accumulations, moderate wind from the west, alpine temperatures drop to -8 C.
THURSDAY: Cloudy with scattered flurries and 5-10 cm of new snow, light wind from the northwest, alpine high temperatures around -6 C.
FRIDAY: Mostly sunny, light wind, alpine high temperatures around -8 C.
SATURDAY: Sunny, light wind, alpine high temperatures around -8 C.
Avalanche Summary
A few large persistent slab avalanches have been triggered in the past few days. On Monday, a size 3 slab avalanche was triggered by a snowmobiler in the Seaton area on a steep northeast-facing slope at 1800 m. The avalanche crown was 100-150 cm thick and ran on basal facets. On Saturday a large snow machine remotely triggered a size 3.5 avalanche in the Kispiox area. The avalanche crown was 50-200 cm thick and ran on buried surface hoar. These events highlight how the recent storms have made buried weak layers more reactive.
Storms over the past week have also resulted in several cycles of natural avalanche activity. Most recently, small to large (size 1-2.5) slab avalanches were reported across the region on Monday and Tuesday, including some in this MIN report from Hankin. Most of the natural avalanche activity was on east-facing slopes that were wind loaded.
Snowpack Summary
10-30 cm of recent snow has rapidly settled due to mild temperatures. In open terrain this snow has been dramatically affected by strong wind from the southwest. Some areas continue to have issues with weak layers that formed during cold weather in January. Depending on location these layers may be composed of soft facets or surface hoar and are typically are buried 60-120 cm below the surface. Crust/facet layers also lurk at the base of the snowpack, especially in shallower (eastern) areas. Most recent signs of instability with these deeper layers have been around Hazelton and Kispiox, but could be a problem on certain slopes anywhere in the region.
Terrain and Travel
- Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Recent storm snow is gradually gaining strength, but will likely remain reactive on wind loaded slopes.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Recent storms have agitated buried weak layers, resulting in some very large persistent slab avalanches. Although these avalanches are only possible in isolated locations, the consequences are severe. Recent areas of concern have been around Kispiox and Hazelton, but any large steep slope should be approached with caution.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 6th, 2020 4:00PM
