Avalanche Forecast
Issued: Mar 27th, 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
Carefully evaluate steep lines for wind slabs before committing to them.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Summary
Confidence
Avalanche Summary
On Saturday there were reports of several small to large wet loose avalanches that started near the alpine on south-facing terrain. There was also a report of a skier-triggered size 1.5 wind slab avalanche that occurred in the alpine.
On Friday, a couple of cornice failures triggered loose dry avalanches up to size 2 on large alpine slopes.
A couple of deep persistent slab avalanches were reported this week. On Wednesday, a cornice fall entrained a mass of snow which then triggered a size 3 deep persistent slab avalanche. It occurred at 2350 m on a north east facing slope. On Tuesday, a size 2.5 deep persistent slab avalanche was reported in the South Chilcotin range, around 2200 m on a south-facing slope.
Snowpack Summary
At higher elevations, moderate southwesterly winds may have transported the 10 to 20 cm of recent snow and formed small wind slabs. Incoming moderate to strong easterly winds may develop new wind slabs where they typically do not occur.
Below the new snow is a melt-freeze crust that exists on all aspects at treeline and below, and on solar aspects to the mountain top. On high north aspects is a mixture of decomposing dry snow and small surface hoar in isolated locations.
The mid-snowpack is generally strong but the lower snowpack is a different story.
A weak layer of sugary facets is still prominent at the base of the snowpack. Small surface avalanches and cornice falls are the most likely things to trigger this layer. However, there remains a significant concern for human triggering in rocky, shallow, or thin-to-thick snowpack areas at treeline and above.
Weather Summary
Monday Night
Cloudy with clear periods, trace accumulation, winds northeast 10 to 20 km/h, freezing levels 1500 m.
Tuesday
Sunny, no accumulation, winds northeast 10 to 20 km/h gusting to 35, freezing levels 1600 m.
Wednesday
A mix of sun and cloud, no accumulation, winds variable and light, freezing levels reaching 1700 m. Thursday
A mix of sun and cloud, no accumulation, winds southerly and light, freezing level to 1800 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Carefully evaluate steep lines for wind slabs.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Avoid exposure to slopes that have cornices overhead.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
Problems
Wind Slabs
Variable light to strong winds may have redistributed recent snow creating wind slabs on all aspests
Aspects: All aspects.
Elevations: Alpine.
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, wind affected terrain where the snowpack depth varies from thick to thin. Especially in the northern part of the region around the Chilcotins, Birkenhead, and Hurley.
Recent natural avalanche activity was observed on this layer, likely triggered by warm temperatures and strong sunshine heating the snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 28th, 2023 4:00PM
