When do mountain climbers need to use ropes?

1. Crossing crevasses: Glaciers often have deep cracks called crevasses, which can be dangerous to cross. Climbers use ropes to set up fixed lines or ladders across crevasses, allowing them to pass safely.

2. Ascending or descending steep sections: Ropes can provide support and safety when climbing or descending steep, exposed sections of a mountain. Climbers may use a technique called "belaying," where one climber anchors themselves and holds the rope while another climber moves up or down.

3. Setting up anchors: Ropes are essential for setting up anchors, which are secure points of attachment on the mountain. Anchors can be used to create fixed lines, belay stations, or to secure climbers in case of a fall.

4. Rescue and self-rescue: In case of an emergency, ropes can be used for rescue purposes. Climbers can use ropes to lower an injured climber, set up a Tyrolean traverse (a rope system used to cross a gap), or create a hauling system to lift someone to safety.

For these reasons, ropes are an essential piece of equipment for mountain climbers, providing safety and support in various challenging situations.