Avalanche Forecast
Issued: Mar 11th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
wlewis,
Avalanche Canada
Plan your travels with aspect in mind. Wind slabs remain possible to trigger on south and west facing slopes. Watch for clearing skies - short periods of sunshine can rapidly increase reactivity on south facing/sun affected slopes.
Continue to avoid thin and rocky start zones where buried weak layers are shallow.
Summary
Confidence
Moderate
Avalanche Summary
Recent avalanche observations have been limited to solar-triggered loose avalanches from steep south aspects.
Last week the region saw numerous natural wind slab and cornice-triggered avalanches up to size 2.
On Tuesday our field team observed a size 3 deep persistent slab avalanche near Hankin that they estimated to be around a week old. The slab propagated across the full steep, rocky feature. This has been the latest of a pattern of intermittent large deep persistent slab activity in the alpine. Observations from late February include a cornice-triggered size 2.5 at Hudson Bay and several explosive controlled size 2-3 near Ningunsaw.
Snowpack Summary
Recent wind affected snow sits over previously hard, wind affected surfaces in the alpine. Sun crust or moist snow can be found on steep solar aspects .In sheltered terrain loose soft snow may still be available for good riding conditions.
Several crusts, layers of facets, or surface hoar can be found in the top 150 cm of the snowpack, but have not shown any significant avalanche activity or snowpack test results recently.
The lower snowpack consists of weak, basal facets which may become active with any rapid change in the snowpack, such as heavy loading or dramatic warming. Avoiding thin and rocky start zones is still recommended.
Weather Summary
Saturday Night
Cloudy with isolated flurries. Moderate southeasterly wind. Freezing level below valley bottom.
Sunday
Mostly cloudy with isolated flurries. Moderate southeasterly wind. Alpine high -9 ËšC.
Monday
Mostly cloudy with light snowfall, up to 5 cm. Light to moderate southeasterly wind. Alpine high -7 ËšC.
Tuesday
Partly cloudy with moderate southwest winds. Alpine high -7 ËšC.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Conditions may have improved, but be mindful that deep instabilities are still present.
Problems
Wind Slabs
Wind slabs remain possible to trigger in terrain features that were reverse-loaded by consistent north/east winds. Wind slabs may sit over a sun crust on south facing slopes. Watch for wind drifted snow below ridge crests and rollovers and in cross-loaded terrain.
Look for signs of active wind transport, newer wind slabs are most reactive.
Aspects: South East, South, South West, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak, sugary crystals at the bottom of the snowpack produced large avalanches in late February. This problem may become active again with any rapid change to the snowpack, such as heavy snowfall, warming or large impacts such as cornice falls.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 12th, 2023 5:00PM
