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 a concern. 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: Flurries continue overnight, with freezing levels dropping to valley bottom. Moderate west-southwest winds.Â
FRIDAY: A mix of sun and cloud, isolated flurries. Freezing level rising to 1600 m. Alpine high of 0. Moderate southwesterly winds.Â
SATURDAY: Partly cloudy, light flurries. Freezing levels reach 1800 m. Moderate southerly winds turn west in the afternoon. Alpine high of +2.
SUNDAY: Around 5 cm possible overnight. Mostly sunny with moderate southwest winds. Freezing levels reaching 1500 m. Moderate southwest winds. Alpine high of -2.
Avalanche Summary
On Wednesday, explosive control south of Renshaw produced avalanches up to size 3 within the recent storm snow. Loose wet activity was triggered at lower elevations to size 2.5.
Natural activity was observed in specific wind loaded features around ridgelines to size 1.5.
Last weekend, numerous natural and sledder-triggered avalanches were reported in the Pine Pass and Renshaw area, all failing on surface hoar. The most reactivity has occurred on wind-loaded, northeast aspects. Most notably, a size 2.5 sledder-triggered avalanche occurred near Bijoux Falls. The full report can be seen here.
Snowpack Summary
40-80 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 hard wind-affected snow, sun crusts on southerly slopes, and large surface hoar on shaded and sheltered slopes. This layer of surface hoar is expected to remain reactive, with the most activity observed in the Pine Pass and Renshaw area.
The mid and lower snowpack is generally well-settled and strong in most areas, with multiple crusts throughout.Â
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Carefully monitor the bond between the new snow and old surface.
- 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.
Problems
Persistent Slabs
Around 40 cm of recent snow sits over a weak layer of surface hoar. Most reactivity has been reported on east-facing slopes, in the Pine Pass and Renshaw areas.
Wind loading has buried this layer up to 100 cm deep and produced large human triggered avalanches this week.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Recent snow and moderate southwest winds have formed wind slabs at higher elevations.
These slabs may be surprisingly deep and propagate widely where they are sitting on a weak layer of surface hoar or a sun crust.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 18th, 2022 4:00PM
