Avalanche Forecast

Archived

Mar 12th, 2025–Mar 13th, 2025

Alpine

Natural and human triggered avalanches likely.

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.

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, Spearhead, Tantalus, Sky Pilot.

Human triggered avalanches are likely. Stick to simple terrain and conservative decision-making is essential.

Natural avalanche activity will spike on solar slopes when the sun is out.

Confidence

Moderate

Avalanche Summary

On Wednesday, more snow than forecast blanketed the Sea to Sky region. We believe a natural avalanche cycle is likely happening this afternoon and into the evening.

On Tuesday, numerous human triggered avalanches up to size 1.5 were reported. Explosive control did trigger a persistent slab avalanche that failed on the mid-February facet interface size 2.

Touchy storm slabs are likely on Friday.

Avoid solar slopes when the sun comes out.

Snowpack Summary

Up to 120 cm of settling storm snow sits above a crust on all aspects except high north facing slopes, where it sits on faceted snow that formed 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

Wednesday Night

Cloudy with isolated flurries. 10 to 40 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level valley bottom.

Thursday

Cloudy with some sunny periods and isolated flurries. 15 to 25 km/h southeast ridgetop wind. Treeline temperature -2 °C. Freezing level 1500 m.

Friday

Cloudy with sunny periods. 10 to 15 km/h southeast ridgetop wind. Treeline temperature -5 °C. Freezing level 1100 m.

Saturday

Cloudy with 5 to 10 cm of snow. 15 to 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 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.
Storm slabs in motion may step down to deeply buried weak layers and result in very large avalanches.
Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Even brief periods of direct sun could produce natural 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.