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
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast. Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.
Weather Forecast
SATURDAY NIGHT: 5-10 cm possible overnight, higher accumulations around 15 cm likely concentrated near Eagle Pass. Moderate southwesterly winds. Freezing levels drop to valley bottom.
SUNDAY: A mix of sun and cloud with light westerly winds. Freezing levels around 1300 m, alpine high of -3.Â
MONDAY: Flurries possible with light southwest winds. Mostly cloudy. Freezing levels rise to 1500 m. Alpine high of -1.
TUESDAY: Freezing levels only push higher, reaching near 2500 m. A mix of sun and cloud. Moderate southwest winds. Alpine high +4.Â
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.Â
On Friday, wind loaded features produced up to size 1.5 natural slab avalanches in many areas.
There is continued evidence of recent natural activity to size 3 on the early march weak layers (primarily south facing slopes) that has occurred within the last 3 days. Natural and rider triggered slab avalanches to size 2 on south and east facing slopes on the crust. Explosive control work Friday produced a size 3 slab, failing on the buried surface hoar layer on a north facing treeline slope.Â
Loose wet avalanches have been reported at elevations below the freezing line over the past 5 days.Â
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 to tests.Â
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.
- 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.
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 20th, 2022 4:00PM
