| What it is | Snow spanning a crevasse |
| Danger | Can hide a crevasse; may collapse |
| Managed by | Roping up, probing, careful crossing |
| Difficulty | Intermediate (hazard) |
A snow bridge is a span of snow that forms over a crevasse, sometimes hiding it completely. Snow bridges can be strong enough to cross or thin enough to collapse under a climber, which is why glacier travelers rope up, probe suspect bridges, and cross them carefully or avoid them.
The hazard
A hidden bridge can conceal a crevasse entirely, so roped glacier travel turns a collapse into a catchable fall rather than a catastrophe.
Crossing one
Probe ahead, cross one at a time with teammates ready to arrest and perform crevasse rescue, and choose the most solid span — or detour.
Frequently asked questions
What is a snow bridge?
A snow bridge is a layer of snow that has built up across the top of a crevasse, forming a span over the gap. Some are obvious; others completely conceal the crevasse beneath, making them one of the trickiest hazards of glacier travel.
Are snow bridges safe to cross?
It depends — a thick, well-consolidated bridge in cold conditions can be solid, while a thin or sun-weakened one can collapse under a climber's weight. Because you often can't be sure, teams rope up so a collapse becomes a catchable crevasse fall rather than a disaster.
How do you test a snow bridge?
Mountaineers probe ahead with an ice axe or pole to feel for the hollow void of a hidden crevasse, cross one at a time with the rope managed and teammates ready to arrest, distribute weight (sometimes crawling), and choose the narrowest, most solid-looking span — or detour around it.
Sources
- Glacier hazards — American Alpine Club