Avalanche Forecast
Issued: Mar 9th, 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.
ahanna,
Avalanche Canada
Rider triggered avalanches are possible on specific terrain features. There are a few factors to consider when evaluating snow and terrain for avalanche potential; including wind and sun exposure as well as elevation and snowpack depth.
Summary
Confidence
Avalanche Summary
Recent avalanche observations have been limited to solar-triggered loose dry out of steep south aspects up to size 1.5 on Wednesday.
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
10-20 cm of recent wind affected snow sits over previously wind-hardened surfaces in the alpine. Sun crust or moist snow can be found on steep solar aspects.
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 or shock to the snowpack, such as heavy loading or dramatic warming.
Weather Summary
Thursday night
Clear. Light easterly wind. Alpine low -14 ˚C.
Friday
A mix of sun and cloud. Moderate southeasterly wind. Alpine high -12 ˚C.
Saturday
Mostly cloudy with isolated flurries and sunny breaks. Moderate easterly wind. Alpine high -16 ˚C.
Sunday
Mostly cloudy with isolated flurries and sunny breaks. Light easterly wind. Alpine high -14 ˚C.
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.
- Conditions may have improved, but be mindful that deep instabilities are still present.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
Problems
Wind Slabs
Recent snow and wind have reverse-loaded fresh wind slabs into atypical terrain features. Watch for wind drifted snow below ridge crests and rollovers and in cross-loaded terrain.
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 reactivate with any rapid change or shock to the snowpack, such as dramatic warming.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 10th, 2023 4:00PM
