Avalanche Forecast
Issued: Mar 3rd, 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
Southerly winds have redistributed recent storm snow.
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
Avalanche Summary
In the last couple of days, there have been numerous reports of storm slab, wind slab, and loose dry avalanches most of these were released naturally and a few were human-triggered. They ranged in size between one and two. Expect to see more of these avalanches if you venture into the back country.
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
Our region saw 30 to 50 cm of storm snow this past week. Southerly winds have begun to redistribute this new snow into reactive wind slabs. New snow and wind slabs sit on a variety of surfaces. 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.
The mid-snowpack is well consolidated. This is not the case for the lower snowpack. 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 200 and 250 cm.
Weather Summary
Friday Night
Partly cloudy, trace accumulation, winds south 10 to 15 km/h, treeline temperatures -10 °C.
Saturday
Mostly sunny, no accumulation, winds east southeast 10 to 20 km/h, treeline temperatures -10 to -7 °C.
Sunday
A mix of sun and cloud, 5 to 8 cm accumulation, winds east 10 to 20 km/h treeline temperatures -8 °C.
Monday
A mix of sun and cloud, no accumulation, winds southwest 10 km/h, treeline temperatures -10 to -5 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be especially cautious as you transition into wind affected terrain.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Keep your guard up at lower elevations. Wind slab formation has been extensive.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Problems
Wind Slabs
The 30 to 50 cm of snow that has accumulated this past week may have been redistributed by variable winds. Expect to find wind slabs below tree line in exposed areas.
Wind slab reactivity may persist for longer than is typical due to the weak surface they are sitting on.
Aspects: All aspects.
Elevations: All elevations.
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 4th, 2023 4:00PM
