Avalanche Forecast
Issued: Mar 16th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
JSmith,
Avalanche Canada
Continued snow and southwesterly wind will form fresh storm slabs reactive to human triggers; especially in wind affected terrain. Choose conservative terrain and watch for signs of instability such as whumphing, cracking, and recent avalanches.
Summary
Confidence
Weather Forecast
TUESDAY NIGHT: Snow; 5-15 cm. / Strong, southwest ridgetop wind / alpine low temperature -5 / Freezing level 700 m.
WEDNESDAY: Snow; 10-20 cm. / Strong, southwest ridgetop wind / alpine high temperature -2 / Freezing level 600 m.
THURSDAY: Cloudy with flurries; 2-5 cm. / Moderate, south ridgetop wind / alpine high temperature 0 / Freezing level 1200 m.
FRIDAY: Snow; 5-10 cm. / Strong, southwest ridgetop wind / alpine high temperature -3 / Freezing level 700 m.
Avalanche Summary
Explosive control work on Monday produced storm slab avalanches up to size 2. Natural wet loose avalanches up to size 1.5 were also observed.
A widespread natural avalanche cycle with storm slab avalanches up to size 4 occured throughout the weekend. Most natural avalanche activity were observed on solar aspects within the storm snow. On polar aspects avalanches may have run on a layer of surface hoar which formed prior to the arrival of the storm.
Snowpack Summary
10-15 cm. of new snow sits on top of last weekend's storm totals ranging from 50 cm. in the north to 150 cm. in the south of the region. Moderate to strong southwesterly winds are forming fresh slabs in lee features at treeline and above. Rain fell below 900 m over the weekend, saturating the upper snowpack. The new snow may overlie a persistent weak layer of surface hoar on northerly aspects and in sheltered terrain features around treeline or a melt-freeze crust on southerly aspects and below treeline.
Around 100 to 300 cm overlies a persistent weak layer buried in mid-February that may still be a concern in isolated parts of the region. The layer consists of surface hoar in areas sheltered from the wind and facets that formed during February's cold snap. Avalanche activity on this layer has mostly occurred west of Terrace along Highway 16 and in the Kitimat area in the past weeks.
The mid and lower snowpack is well settled and strong in most areas.
Terrain and Travel
- Storm slab size and sensitivity to triggering will likely increase through the day.
- Choose conservative terrain and watch for clues of instability.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Avoid exposure to slopes that have cornices overhead.
Problems
Storm Slabs
Continued snow and southwesterly winds are forming fresh storm slabs; especially in wind affected terrain.
Recently formed slabs may be sitting on a weak layer of surface hoar on northerly aspects and in sheltered terrain or a crust on solar aspects and lower elevations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 17th, 2021 4:00PM
