Issued: Mar 28th, 2023 4:00PM
The alpine rating is Wind Slabs, Deep Persistent Slabs and Loose Wet., the treeline rating is , and the below treeline rating is Known problems include
A relatively stable snowpack in the morning will deteriorate with rising temperatures, solar input, and little wind to cool things off.
Avoid solar slopes during the height of the day.
Two size-one wind slab avalanches were reported on Monday. These were skier controlled and naturally caused. They were on north-facing aspects and were at a depth of 5 cm failing on the recent snow.
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 last week. Last 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. Last Tuesday, a size 2.5 deep persistent slab avalanche was reported in the South Chilcotin range, around 2200 m on a south-facing slope.
Strong easterly winds may develop new wind slabs where they typically do not occur in a process called reverse loading.
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.
Clear, no accumulation, winds northeast 10 to 20 km/h gusting to 35, freezing levels dipping down to valley bottom.
Sunny with a few clouds, no accumulation, winds switching from the northeast to the southwest light, freezing levels reaching 2000 m.
Sunny in the morning with clouds increasing throughout the day, no accumulation, winds southwest 15 km/h, freezing level to 1800 m.
Cloudy, 8 to 10 cm accumulation starting Thursday evening, winds southwest 15 km/h, freezing level 1200 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Carefully evaluate steep lines for wind slabs.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
- Avoid exposure to slopes that have cornices overhead.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Light to strong winds may have redistributed recent snow creating wind slabs.
Aspects: South East, South, South West, West, North West.
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.
The probability of small wet loose avalanches will increase on solar slopes during daytime peak warming.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Valid until: Mar 29th, 2023 4:00PM