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. 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 continue with mostly cloudy skies, around 5 cm expected. Moderate southwesterly winds. Freezing levels drop to 800 m.
SATURDAY: Scattered flurries with mostly cloudy skies, 5 cm possible over the day. Moderate southwesterly winds. Freezing levels rise to 1600 m. Alpine high of +1.
SUNDAY: 5-10 cm possible overnight. A mix of sun and cloud with light westerly winds. Freezing levels around 1300 m, alpine high of -3.
MONDAY: Light snowfall with light southwest winds. Freezing levels rise to 1500 m.
Avalanche Summary
On Thursday, numerous reports noted whumpfing and settlements in the weak layers. Large, naturally triggered storm slabs were observed on south facing slopes where the storm snow sits over a crust. A cornice fall also triggered a size 1.5 avalanche on the buried surface hoar layer on a north facing slope. This interface is still reactive to human triggers, with remotely triggered avalanches reported. Explosive control work produced size 2.5-3 slab avalanches, with impressive propagation on south facing slopes.
Loose wet avalanches have been reported at elevations below the freezing line.
On Wednesday, avalanche activity was reported to size 2.5. Avalanches were naturally and human triggered, mainly occurring on the buried weak layers below the storm snow. Activity mainly occurred on south and east facing slopes around treeline,
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
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- 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.
Most reactivity has been seen around Malakwa (Queest/Gorge area), Highway 23 North (Downie Creek and Goldstream FSR areas) and terrain surrounding Valemount and Blue River.
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
