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Avalanche Forecast

Archived

Mar 11th, 2025–Mar 12th, 2025

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Coquihalla, Manning, Skagit.

Storm slabs may be reactive to human triggering, especially at upper elevations.

Careful snowpack evaluation, cautious route-finding, and conservative decision-making are essential.

Confidence

Moderate

Avalanche Summary

No new avalanches reported by Tuesday afternoon.

Storm slabs may be reactive to human triggers on Wednesday, especially at treeline and in the alpine on leeward slopes that have seen more wind loaded snow.

If you are headed to the backcountry, please consider sharing your photos and observations from your day on the Mountain Information Network.

Snowpack Summary

Up to 30 cm of storm snow blankets the region. Moderate southwest winds have redistributed storm snow into deeper pockets on lee slopes at the ridgeline. Storm snow covers a crust on all aspects except on high north-facing terrain, where new snow buries up to 20 cm of snow overlying a crust from earlier in March.

A layer of facets and surface hoar from late January can be found down 50 to 120 cm.

The lower snowpack contains several crusts that are not concerning.

Weather Summary

Tuesday Night

Cloudy with 3 to 8 cm of snow. 20 to 40 km/h south ridgetop wind. Treeline temperature -1 °C. Freezing level 1000 m.

Wednesday

Cloudy with 10 cm of snow. 20 gusting to 60 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1600 m.

Thursday

Cloudy. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -5°C. Freezing level 500 m.

Friday

Mix of sun and cloud with a trace of new snow. 20 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1200 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid freshly wind-loaded terrain features.
  • Keep your guard up as storm slabs may remain sensitive to human triggering.
  • Storm slabs in motion may step down to deeper layers resulting in 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.