Avalanche Forecast
Issued: Mar 17th, 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 to triggers. Stick to conservative terrain with minimal overhead hazard and watch for signs of instability like whumpfing, natural avalanches and cracking.
Find more information on this tricky layer here.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
THURSDAY NIGHT: Up to 10 cm of snowfall possible overnight. Moderate southwesterly winds. Freezing levels drop to 500 m.Â
FRIDAY: Scattered flurries continue with mostly cloudy skies. Moderate southwesterly winds. Freezing levels rise to 1500 m. Alpine high of -1.
SATURDAY: Scattered flurries with mostly cloudy skies, 5 cm possible over the day. Moderate southwesterly winds. Freezing levels rise to 1700 m. Alpine high of +1.
SUNDAY: 5-10 cm possible overnight. A mix of sun and cloud with moderate northwesterly winds. Light westerly winds. Freezing levels around 1300 m, alpine high of -3.Â
Avalanche Summary
Reports from Wednesday continue to indicate a reactive and unstable snowpack.Â
- Several natural slab avalanches up to size 2 were reported within the most recent 25 cm of storm snow.
- Numerous human triggered avalanches were also reported, with several remotely triggered avalanches occurring on the buried weak layers of surface hoar, facets and crust. Activity mainly occurred on south and east facing slopes around treeline, producing avalanches up to size 2.5.
On Tuesday, numerous natural and human triggered avalanches were reported on these same layers.
Snowpack Summary
40-60 cm of settling storm snow is being redistributed into wind loaded features at higher elevations. At lower elevations moist snow or a melt-freeze crust likely exists from recent rain and warm temperatures.
This new snow is sitting on various surfaces, including sun crusts on southerly slopes, facetted snow, and isolated pockets of surface hoar. The new snow is bonding poorly to this old surface, producing large avalanches within the last 3 days.Â
The late February persistent weak layer combination of crust, facets and surface hoar is down 30-40 cm. Reports suggest this layer is not a problem in most areas. Two persistent weak layers from mid-February and late January are buried 50-120cm deep. No recent avalanches have been reported on these layers.
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.
- On south facing slopes a layer of crust and facets can be found at all elevations.
- On other aspects, a large layer of surface hoar is most concerning 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 18th, 2022 4:00PM
