This is an archived bulletin related to a fatal incident Mar 24 - Not Current

Date Issued: Sun, March 23, 2025 at 16:00 PT
Valid Until: Mon, March 24, 2025 at 16:00 PT
Prepared by: Avalanche Canada

A warm, wet storm is creating dangerous avalanche conditions. Avoid avalanche terrain.

Danger Ratings
Monday: Alpine, Treeline, Below Treeline: 4 - High

Terrain and Travel Advice

    Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.
    Be aware of the potential for large avalanches due to buried weak layers.
    Only the most simple non-avalanche terrain with no overhead hazard is appropriate at this time.

Problems

Avalanche Problem 1: Storm slab
Elevation: Below treeline, Treeline, Alpine
Slopes: North, Northeast, East, Southeast, south, Southwest, West, Northwest
Chances of Avalanches: Very likely
Expected Size: Small - Large

Another 10 to 20 cm of new snow will add to the existing storm storm slab problem. Wind-loaded slopes will be especially dangerous.

Avalanche Problem 2: Persistent slab
Elevation: Treeline, Alpine
Slopes: North, Northeast, East, West, Northwest
Chances of Avalanches: Possible - Likely
Expected Size: Large - Large

Several persistent weak layers exist in the upper metre of the snowpack. Small avalanches in motion may trigger these deeper layers creating large and destructive avalanches.

Avalanche Summary

Storm slabs have produced many size 1 to 2 avalanches in recent days, including numerous human-triggered slabs in the top 30 cm and larger natural avalanches in alpine terrain.

Large natural and artificially triggered persistent slab avalanches to size 3 were reported most recently on Saturday.

Expect continued storm slab activity on Monday. Persistent slab avalanches will become increasingly likely as temperatures warm this week.

Snowpack Summary

Continued snowfall over the day Monday will bring storm totals into the range of 50 to 70 cm.

Several weak layers in the snowpack are currently concerns for triggering persistent slab avalanches:

    Facets/surface hoar/crust from early March buried 50 to 80 cm deep,

    Facets/surface hoar/crust from mid-February buried 70 to 100 cm deep, and

    Facets/surface hoar/crust from late January buried 100 to 150+ cm deep.

This complex snowpack combined with dynamic weather makes travel in avalanche terrain dangerous.

Weather Summary

Sunday night

15 to 30 cm of snow, turning to rain below 1600 m. 40 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level rising to 2000 m.

Monday

10 to 20 cm of snow, rain below 1500 m. 30 to 40 km/h southwest ridgetop winds. Treeline temperature +2 °C. Freezing level 2000 m, rising to 2400 m.

Confidence: High - We are confident the snowpack will rapidly lose strength with the arrival of the forecast weather.