| What it is | A deep crack in a glacier |
| Danger | Often hidden by snow bridges |
| Managed by | Roping up, crevasse rescue |
| Found on | Glaciers |
A crevasse is a deep crack in a glacier formed as the ice moves over uneven terrain. Crevasses can be tens of metres deep and are often hidden beneath snow bridges, making them one of the principal hazards of glacier travel. Mountaineers rope up and learn crevasse rescue to manage the danger.
The hidden danger
A thin snow bridge can hide a crevasse completely, so teams rope up for glacier travel and carry crevasse rescue skills.
Crevasse vs bergschrund
The crevasse at a glacier’s head is a bergschrund — see crevasse vs bergschrund.
Frequently asked questions
What is a crevasse?
A crevasse is a deep fracture in a glacier that opens up as the ice flows over bumps, bends, and steepenings in the ground beneath. They can be wide and very deep, and are the defining hazard of traveling on glaciated terrain.
How deep are crevasses?
Crevasses commonly reach 20-40 metres deep and can be deeper, narrowing with depth as the ice becomes more plastic. A fall into one can be fatal from the impact, from becoming wedged, or from cold — which is why rescue skills matter.
How do climbers avoid crevasses?
By traveling roped together as a team, reading the glacier's surface for telltale sags and depressions that hint at hidden crevasses, probing suspect snow bridges, and choosing routes that minimize crossings. Even so, hidden crevasses mean roped travel and rescue readiness are essential.
Sources
- Glacier hazards — American Alpine Club