Avalanche Forecast
Issued: Mar 24th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs.
jsmith,
Avalanche Canada
Avoid rocky, shallow, or thin-to-thick snowpack areas in the alpine where triggering slabs is more likely.
When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
Summary
Confidence
High
Avalanche Summary
A naturally triggered size 2 wet loose avalanche was reported on a northwest aspect in the alpine on Thursday. The avalanche stepped-down to weak facets at the bottom of the snowpack.
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.
A size 2.5 deep persistent slab avalanche was reported Tuesday in the South Chilcotin range, around 2200 m on a south-facing slope.
Snowpack Summary
5-10 cm of new snow and light to moderate southwest wind on Thursday night.
Below the new snow is a melt freeze crust exists on all aspects at treeline and below, and on solar aspects to mountain top. The only exception is high north aspects which had 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, which would result in a very large and destructive avalanche.
However, there remains a significant concern for human triggering in rocky, shallow, or thin-to-thick snowpack areas at treeline and above.
Weather Summary
Friday Night
Mostly cloudy with isolated flurries; 0-10 cm / 10 km/h southwest ridgetop wind / Low temperature at treeline around -7 C / Freezing level valley bottom
Saturday
Mostly cloudy with isolated flurries; 0-3 cm / 10 km/h southwest ridgetop wind / High temperature at treeline around -4 C / Freezing level 1300 m
Sunday
Mix of sun and cloud / 10 km/h southwest ridgetop wind / High temperature at treeline around -4 C / Freezing level 1300 m
Monday
Sunny / 20 km/h east ridgetop wind / High temperature at treeline around -1 C / Freezing level 1500 m
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- 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
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 25th, 2023 4:00PM
