Avalanche Forecast
Issued: Mar 18th, 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.
wlewis,
Avalanche Canada
Buried weak layers continue to be reactive, especially throughout the Selkirks. Avalanches are likely where recent storm snow sits over a sun crust or surface hoar layer.
Stick to conservative terrain and watch for signs of instability.
Summary
Confidence
Weather Forecast
FRIDAY NIGHT: Scattered flurries with partly cloudy skies. Moderate southwest winds. Freezing levels drop to 800 m.
SATURDAY: Scattered flurries with partly cloudy skies, 5-10 cm possible over the day. Moderate southwest winds. Freezing levels rise to 1600 m. Alpine high of +2.
SUNDAY: Another 5-10 cm possible overnight. Scattered flurries with partly cloudy skies. Moderate westerly winds. Freezing levels around 1400 m, alpine high of -3.
MONDAY: Light snowfall with moderate southwest winds. Mostly cloudy, freezing levels reach 1500 m.
Avalanche Summary
On Thursday, natural avalanches were observed to size 2.5. Human triggered avalanches (including remote triggers) were reported to size 2. Most activity occurred on south and east facing slopes at treeline, where storm snow sits over a crust.
Wind slabs were reactive to human triggers in lee terrain features to size 1.5. And loose wet activity was observed on sun affected slopes.
On Wednesday, several natural avalanches up to size 2.5 were reported in wind loaded terrain features. Numerous human triggered avalanches to size 2.5 were reported on the buried weak layers.
A recent report from the Valkyr Range indicates uncertainty surrounding the persistent weak layers buried within the snowpack.
Snowpack Summary
Up to 60 cm of recent settling storm snow sits over a layer of weak surface hoar in sheltered and shaded terrain, and over a crust on south facing slopes. Test results show that the new snow is bonding poorly to old surfaces in many areas, producing large avalanches within the last 3 days.
At higher elevations consistent southwest winds are creating deeper deposits on north through east facing features. Below 1500 m, moist snow or a melt-freeze crust likely exists from recent rain and warm temperatures.
The late February persistent weak layer combination of crust, facets and surface hoar is down 70-90 cm. Two persistent weak layers from mid-February and late January are buried 100-170cm deep. Avalanches on these layers are unlikely to be triggered.
Terrain and Travel
- 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.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Persistent Slabs
New snow continues to add load to a weak layer buried 30-60 cm deep. Large avalanches have been triggered on these layers within the last 3 days.
- A layer of crust and facets can be found at all elevations on sun affected slopes (south through east)
- On other aspects, a large layer of surface hoar may be preserved on sheltered treeline slopes.
More information can be found here in the new forecaster blog.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Expect freshly wind loaded features to be reactive to human triggers as southwest winds continue.
Be aware that small avalanches in motion may step down to deeper layers.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 19th, 2022 4:00PM
