Key takeaways
- A chimney is a crack wide enough to climb inside with your whole body.
- You ascend by pressing against both walls (e.g., back-and-foot) using counter-pressure.
- It's distinct from hand/finger crack climbing — it's whole-body opposition, not jamming.
- Width matters: comfortable chimneys are secure; very wide or narrow ones are awkward and strenuous.
What a chimney is
A chimney is a rock crack or fissure wide enough for a climber to fit their entire body inside. Rather than jamming hands or fingers as in narrower cracks, you climb a chimney by pressing against the two opposing walls with your body and using counter-pressure to move up.
How to climb one
The classic technique is back-and-foot: press your back against one wall and your feet (and hands) against the opposite wall, using the opposition to hold yourself in place, then shuffle upward by alternately moving your back and feet. It relies on counter-pressure and body positioning, not gripping holds.
Inside a body-width chimney with no holds, a climber wedges their back against one wall and pushes their feet flat against the other — the opposing pressure holding them secure — then inches upward by walking their feet up and re-pressing their back, resting whenever the position allows.
Width and difficulty
Difficulty depends heavily on width: a well-sized chimney can feel secure and even restful, while very wide ones (hard to bridge) and narrow ones (a tight squeeze) turn awkward and strenuous. Chimneys can also be hard to protect with gear. Narrower than a chimney is the dreaded offwidth; the opposition technique relates to stemming in a dihedral.
The bottom line
A chimney is a body-width crack you climb from the inside, pressing against both walls with counter-pressure (classically back-and-foot) rather than jamming holds. Well-sized ones feel secure and even restful; too-wide or too-narrow ones turn awkward and strenuous, and they're often hard to protect. Chimneying is a distinctive whole-body climbing skill all its own.
Frequently asked questions
What is a chimney in climbing?
A chimney is a rock crack or fissure wide enough for you to fit your entire body inside. Instead of jamming hands or fingers as in narrower cracks, you climb a chimney by pressing your body against the two opposing walls and using counter-pressure to move upward. They're a distinctive, sometimes awkward, type of climbing feature.
How do you climb a chimney?
The classic technique is back-and-foot: you press your back against one wall and your feet (and hands) against the opposite wall, using the opposing pressure to hold yourself in place, then shuffle upward by alternately moving your back and feet. Other techniques apply depending on the chimney's width. It relies on counter-pressure and body positioning rather than gripping holds.
Are chimneys easy or hard?
It depends heavily on width. A well-sized chimney can feel secure and relatively restful, since the opposing walls support you. But very wide chimneys (hard to bridge) and narrow ones (a tight squeeze) become awkward and strenuous, and chimneys can be tricky to protect with gear, so they range from straightforward to genuinely challenging.
Sources
- Crack & chimney technique — American Alpine Club
- Climbing skills — The Mountaineers