Avalanche Forecast

Archived

Mar 8th, 2024–Mar 9th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Sea To Sky, Brandywine, Homathko, Spearhead.

Very dangerous avalanche conditions exist. Manage the uncertainty around buried weak layers by sticking to low-angle non avalanche terrain and avoiding overhead hazard.

Confidence

Moderate

Avalanche Summary

Thursdays was very active for avalanche observations and occurrences. Many persistence slab avalanche where triggered during explosive work and where large (size 3) . These avalanches had crowns greater than 100 cm in depth and 100 to 200 meters wide. A few avalanche where remote triggered by skiers.

On Wednesday 2 notable large (size 2) one a skier and one that was remotely triggered avalanches where reported in the whistler region.

Snowpack Summary

Storm snow amounts are forecast around 40 cm and overlie a variety of surfaces including surface hoar. Expect strong south winds to strip snow from ridgelines and exposed features and deposit new snow into deep pockets in lee aspect terrain.

Under the new snow an estimated 120-160 cm of progressively resistant or 'right side up' snow is continuing to settle above the problematic crust/facet/surface hoar layer beneath it. This layer continues to show sensitivity to human triggers, and is most concerning at treeline elevations where weak grains like facets and surface hoar are more easily preserved.

Weather Summary

Friday night

Cloudy increasing snowfall bringing 20-40 cm of new snow, 50-90 km/h southwest alpine wind. Treeline temperature -2 °C with freezing level rising to 1200 m.

Saturday

Cloudy with snowfall bringing 15-25 cm of new snow, continuing overnight. 60-80 km/h southwest alpine wind. Treeline temperature around -2 °C with freezing level rising to 1200 m.

Sunday

Cloudy with continuing heavy snowfall bringing 10-20 cm of new snow and 2-day totals to 50-80 cm. 20-40 km/h southwest alpine wind. Treeline temperature -2°C with freezing level around 1200 m.

Monday

Cloudy with snowfall bringing 5-10 cm of new snow. 40-60 km/h southwest alpine wind. Treeline temperature -2°C with freezing level around 1200 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Travel in alpine terrain is not recommended.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Avoid traveling in runout zones. Avalanches have the potential to run to the valley floor.
Remote triggering is a concern, watch out for adjacent and overhead slopes.

Problems

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.

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.