Avalanche Forecast

Archived

Feb 29th, 2024–Mar 1st, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Sea To Sky, Brandywine, Garibaldi, Homathko, Powell River, Spearhead, Tantalus, Sky Pilot.

Dangerous avalanche conditions continue. Natural and human-triggered avalanches are likely.

Stick to simple, non-avalanche terrain without exposure to overhead slopes.

Confidence

Moderate

Avalanche Summary

No new reports by 4 pm Thursday.

On Wednesday, a natural storm slab avalanche cycle was reported at all elevations up to size 1.5. We suspect larger avalanches have occurred but field observations tend to be limited during the storm. Operators who were out reported that the new snow was very reactive to rider triggers and showed a poor bond to the old, firm snow beneath.

Natural, and human-triggered avalanche activity will likely continue on Friday.

Snowpack Summary

50 to 100 cm of storm snow overlies wind-affected surfaces and old wind slabs in exposed areas at all elevations.

Multiple weak layers exist in the upper and mid snowpack. The most concerning weak layer is found down 50 to 120 cm and is composed of a layer of facets or in isolated areas preserved surface hoar above a thick crust. This layer is the culprit of recent remotely-triggered avalanches in low-angle terrain. Professionals are concerned about how this layer will react to the new snow load.

Weather Summary

Thursday Night

Cloudy with snow 5 to 10 cm. Ridgetop wind 25 gusting to 60 km/h southwest ridgetop wind. Treeline temperature -7 °C. Freezing levels valley bottom.

Friday

Cloudy with sunny periods. 15 to 45 km/h south ridgetop wind. Treeline temperature -5 °C. Freezing level 800 m.

Saturday

Cloudy with sunny periods and isolated flurries. 15 to 35 km/h southeast ridgetop wind. Treeline temperature -7 °C. Freezing level hovers around 900 m.

Sunday

Cloudy with sunny periods and isolated flurries. Light southeast ridgetop wind. Treeline temperature -7 °C. Freezing level hovers around 900 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Remote triggering is a concern, watch out for adjacent and overhead slopes.
Brief periods of sun could quickly initiate natural avalanche activity.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.