Avalanche Forecast
Issued: Mar 2nd, 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.
rgoddard,
Avalanche Canada
Reactive wind slabs should be expected.
Use caution in exposed areas and avoid pockets of wind-deposited snow.
Keep in mind that if triggered, wind slabs may step down to the deep persistent slab problem resulting in large avalanches.
Summary
Confidence
Moderate
Avalanche Summary
Backcountry users reported accidentally triggering two size 1 wind slab avalanches on Wednesday.
On Monday, loose dry sluffing from steep terrain was seen as well as a remotely triggered wind slab avalanche size 1.5 that reportedly failed on facets below the recent storm snow.
A week ago, two size 3 deep persistent slab avalanches were observed just north of the Hurley summit. One was on a north-facing alpine face and the other an exposed, east-facing open slope at treeline.
Last Friday, two large (size 3-4) natural deep persistent slabs were observed on south and southeast alpine faces in the Birkenhead. We suspect these slabs occurred as a result of wind-loaded from strong northwesterly winds.
These avalanches remind us that the deep persistent slab problem remains in our region and you should make your terrain choices accordingly.
Snowpack Summary
Another 5 to 10 cm of accumulation will fall by mid-day on Friday. This will add to 35 to 50 cm of storm snow that has fallen since last weekend. In some areas, this new snow has bonded poorly to the stiff wind slabs and near-surface faceting formed by recent wind and cold temperatures.
A melt-freeze crust from late January can be found down 70 to 100 cm. At the moment this layer appears to be gaining strength though in isolated areas small facets can still be found above the crust.
There is a widespread weak layer of large sugary facets at the bottom of the snowpack. Recent avalanche activity on this layer has been confined to northern parts of the region in the Chilcotins. Snowpack depths around treeline range between 150 to 250 cm.
Weather Summary
Thursday Night
Cloudy, up to 5 cm accumulation, winds southwest 20 km/h, treeline temperatures -10 °C.
Friday
Cloudy with sunny periods, 2 cm accumulation, winds southwest 25 km/h gusting to 55, treeline temperatures -10 °C.
Saturday
A mix of sun and cloud, trace accumulation, winds northeast 15 km/h, treeline temperatures -10 to -5 °C.
Sunday
Mostly cloudy, 2 to 8 cm accumulation, winds southeast 10 to 20 km/h.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
- Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Problems
Wind Slabs
New snow accompanied by strong southwest wind on Thursday may build fresh wind slabs on lee slopes. Wind earlier this week combined with last weekend's storm snow has varied in direction so watch for wind slabs on all aspects.
Wind slab reactivity may persist for longer than is typical due to the weak surface they are sitting on.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of weak facets sits near the base of the snowpack. This layer is most likely to be problematic in steep, unsupported, wind-loaded terrain in the northern part of the region around the Chilcotins, Birkenhead, and Hurley.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 3rd, 2023 4:00PM
