Avalanche Forecast
Issued: Mar 19th, 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
Conservative terrain choices are advised, buried weak layers still remain reactive on specific features.
Expect avalanche danger to increase as the sun hits the snowpack. Triggering avalanches will become more likely on sun affected slopes.
Summary
Confidence
Weather Forecast
SATURDAY NIGHT: 5-15 cm possible overnight. Higher accumulations around 15 cm may be seen north of Trout Lake. Moderate southwest winds. Freezing levels drop to valley bottom.
SUNDAY: Scattered flurries with a mix of sun and cloud. Moderate westerly winds. Freezing levels around 1400 m, alpine high of -3.
MONDAY: Mostly cloudy with flurries, and moderate southwest winds. Freezing levels reach 1600 m, with alpine highs of 0.
TUESDAY: Freezing levels only push higher, reaching 2500 m. A mix of sun and cloud. Light to moderate southwest winds, alpine high of +4.
Avalanche Summary
Overall reports indicate a gradual tapering of reactivity of the buried weak layers, however reactivity remains in specific features where these weak layers are more prominent.
Reports indicate continued natural avalanche activity throughout the region within the last 3 days. Naturals were observed on Friday up to size 2 in north facing treeline features. Remotely triggered avalanches were reported to size 1, within the storm snow and on the crust buried on south facing slopes.
A notable size 2.5 was triggered on a wind loaded feature on a northwest facing slope at 2100 m. This likely failed on the buried surface hoar.
Wet avalanche activity has been observed on south facing slopes during intense sunshine, and on all aspects below the freezing line throughout the week.
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 and reactive results on testing.
At higher elevations consistent southwest winds are creating deeper deposits on north through east facing features. Below 1700 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.
- 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.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
Problems
Persistent Slabs
Buried weak layers continue to produce large natural and rider triggered avalanches. Short periods of sunshine may increase likelihood of triggering on south facing features.
- A layer of crust and facets can be found at all elevations on sun affected slopes (south through east) in most terrain.
- On shaded slopes, a layer of surface hoar may be preserved in sheltered treeline features. This layer is less widespread but still reactive.
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 20th, 2022 4:00PM
