Trundling, the act of freeing loose rocks on a rock climbing route, can be very dangerous if done improperly.
The idea is to release the loose rocks intentionally so that a climber later on doesn’t do it accidentally, but there’s still risk involved.
You should always make sure that nobody else is in the area, and that you’re an experienced climber. You can easily hurt yourself or others if done improperly.
The video below shows a climber freeing what he calls a ‘death flake’ from the Horns of Jericho in Yosemite National Park.
Video uploaded to YouTube by Kevin DeWeese: “This loose flake was sitting on top of a feature that you climb around. Situated above the belay anchor, I was worried that future parties might be hurt so I pushed it off with my hands until it fell back against them and I thought better of it and used my foot to torque it off the wall.”