Avalanche Forecast
Stick to low-angle terrain away from overhead hazard. Warm temperatures and a complex snowpack are causing multiple avalanche problems.
Confidence
Moderate
Avalanche Summary
A significant avalanche cycle occurred over the weekend, with very large slab avalanches (up to size 4) failing on multiple persistent weak layers. On Sunday, skiers remotely triggered a size 3 persistent slab near Shames (see photo). Sunny weather on Monday also triggered some wet avalanches.
Snowpack Summary
Mild temperatures are rapidly settling the 50 to 100 cm of storm snow from the past week. Wet snow and crusts likely extend up to 1500 m.
Three persistent weak layers are a concern in the snowpack. Surface hoar that formed in mid-March can be found 50 to 100 cm below the snow surface. Below this, another layer of surface hoar that formed in early March can be found at a depth of 100 to 150 cm. Additionally, a layer of facets, surface hoar, and/or a crust from mid-February is buried 100 to 200 cm deep.
Weather Summary
Tuesday Night
Mostly cloudy. 10 km/h northeast ridgetop wind. Treeline temperature 0 °C. Freezing level 1500 m.
Wednesday
Mostly cloudy. 40 km/h northeast ridgetop wind. Treeline temperature +2 °C. Freezing level 1500 m and up to 2000 m along the coast.
Thursday
Cloudy with 2 to 5 cm of snow. 50 km/h east ridgetop wind. Treeline temperature -1 °C. Freezing level 1300 m.
Friday
Mix of sun and cloud. 30 km/h east ridgetop wind. Treeline temperature -2 °C. Freezing level 1200 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Be aware of the potential for large avalanches due to buried weak layers.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
Avalanche Problems
Persistent Slabs
Surface hoar and facets in the upper snowpack caused very large avalanches over the weekend. These layers could be triggered by smaller avalanches, cornice failures, or human activity.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3.5
Storm Slabs
Avalanches in recent storm snow remain possible, especially on wind-loaded slopes near ridges.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2
Loose Wet
Above-freezing temperatures will weaken the surface and trigger wet loose avalanches in steep terrain, especially if the sun comes out.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 1.5