| What it is | A steep, narrow mountain gully |
| Often | Filled with snow or ice |
| Hazard | Channels rockfall & avalanches |
| Difficulty | Intermediate to advanced |
From the French couloir, meaning 'corridor' or 'passage'.
A couloir is a steep, narrow gully on a mountainside, often filled with snow or ice, that provides a natural line of ascent or descent. Couloirs are classic alpine and ski-mountaineering routes, but they channel rockfall, avalanches, and meltwater, so timing and hazard awareness are critical.
The word is French for ‘corridor’.
Why climbers use them
A couloir is a weakness in steep terrain — a logical line up or down — but its funnel shape concentrates objective hazards like rockfall and avalanches.
Staying safe
Climb couloirs early, when snow is frozen and stable (an alpine start), and avoid them when warm or loaded.
Frequently asked questions
What is a couloir?
A couloir is a steep, narrow gully running up a mountain face, frequently holding snow or ice. Couloirs offer logical lines for climbing and ski mountaineering because they're weaknesses in steep terrain, but their funnel shape concentrates hazards.
How do you pronounce couloir?
It's pronounced roughly 'COOL-wahr', from the French word for a corridor or passage — an apt description of these narrow mountain channels.
Are couloirs dangerous?
They can be. Because a couloir funnels everything above it, it channels rockfall, avalanches, and meltwater straight down the line you're climbing. Climbers manage this with early alpine starts (when frozen and stable), good timing, and avoiding couloirs when conditions are warm or loaded.
Sources
- Alpine terrain and hazards — American Alpine Club