Avalanche Forecast
Issued: Mar 1st, 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
7am update: Strong winds have hammered the snow surface at upper elevations. Reactive wind slabs may exist lower in start zones than usual. Be mindful that deep instabilities still exist and are most likely to be triggered from thin, rocky spots.
Summary
Confidence
Moderate
Avalanche Summary
Avalanche observations from this week have been limited to loose dry sluffing. Last week, several large deep persistent slab avalanches were reported in the alpine, including a natural size 3 near Kispiox, a cornice-triggered size 2.5 at Hudson Bay and several explosive controlled size 2-3 near Ningunsaw.
Looking forward, wind slab avalanches can be expected, with potential to step down to those deep instabilities, resulting in large, destructive avalanches.
Snowpack Summary
Extensive wind effect characterizes the snow surface at upper elevations. Wind slabs may be found sitting unusually low down in start zones and lees. Many exposed windward aspects have been scoured. In sheltered areas, 40-50 cm of recent snow may be sitting over a layer of small facets.
Several other crusts, layers of facets, or surface hoar can be found in the top 150 cm of the snowpack, but are not of great concern at present.
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. Snowpack depths range from 60 to 280 cm at treeline.
Weather Summary
Wednesday night
5-10 cm new snow. Strong southwest wind easing. Alpine low -10 ºC.
Thursday
Around 5 cm new snow. Wind easing to light southwest. Alpine high -8 ºC.
Friday
A mix of sun and cloud. Light southerly wind. Alpine high -12 ºC.
Saturday
Mostly sunny. Light easterly wind. Alpine high -10 ºC.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Dial back your terrain choices if you are seeing more than 20 cm of new snow.
- Avoid freshly wind loaded terrain features.
- Keep your guard up at lower elevations. Wind slab formation has been extensive.
- Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Recent winds have hammered the surface at wind-exposed elevations. Wind slabs may be found unusually low in start zones due to recent strong winds.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak, sugary crystals at the bottom of the snowpack have produced large avalanches recently. These avalanches are most likely to be triggered by large loads such as cornice falls. But they can also be triggered by the weight of a person from shallow snowpack areas, and propagate out to deeper snow resulting in large, destructive avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 2nd, 2023 4:00PM
