Avalanche Forecast

Archived

Mar 13th, 2025–Mar 14th, 2025

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 unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Sea To Sky, Brandywine, Garibaldi, Homathko, Spearhead, Tantalus.

Reactive storm slabs are likely at upper elevations. Stick with a conservative trip plan and watch for signs of instability.

Winter isn't over yet. Check out the new forecaster blog here.

Confidence

Moderate

Avalanche Summary

On Wednesday, numerous human-triggered and explosieve-triggered storm slab avalanches were reported up to size 1.5 at treeline and below. Alpine observations were very limited due to the stormy conditions and poor visibility, but we suspect natural avalanches occurred.

Reactive storm slabs are likely on Friday, especially at upper elevations (northerly slopes) that see more wind loaded snow. Natural avalanche activity can spike on solar slopes when the sun is out.

Snowpack Summary

Another 30 cm blanketed the region by Thursday morning. Up to 120 cm of storm snow sits above a crust on all aspects except high north-facing slopes, where it sits on faceted snow that formed in early March. Strong southwest winds have redistributed storm snow into toucy slabs on leeward slopes at the ridgeline. Below treeline the storm snow is settling out rapidly.

A layer of facets and surface hoar from mid February can be found down 100 to 140 cm.

Another layer of facets and surface hoar from late January can be found down 140 to 200 cm.

Weather Summary

Thursday Night

Cloudy with some clear periods and flurries up to 5 cm. 15 to 20 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level valley bottom.

Friday

Cloudy with some sunny periods and isolated flurries. 10 to 20 km/h southeast ridgetop wind. Treeline temperature -4 °C. Freezing level 1100 m.

Saturday

Cloudy with 5 to 10 cm of snow. 25 to 40 km/h south ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 m.

Sunday

Cloudy with snow 5 to 10 cm. 15 to 40 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid lee and cross-loaded slopes at alpine and treeline elevations.
Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Even brief periods of direct sun could produce natural avalanches.
Storm slabs in motion may step down to deeply buried weak layers and result in very large avalanches.

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.