30 August 2022
The Mount Elbrus boulder video
The video, which should be visible below, was captured by Alex09spartak, who seems to be Алекс Никифоров, which Google translate turns into Alex Nikiforov. The original version of the video was posted on Tiktok, which provides the full sequence (and is actually much better than the edited Youtube version).
I am not sure as to where the rockfall occurred, but the mountain is at 43.37, 42.45.
The boulder appears to detach from a large area of loose rock. In the early part of the video the boulder is rotating around its shortest axis – as I have noted previously, this allows the boulder to accelerate quickly and to bounce.
The Mount Elbrus boulder rotating around its shortest axis. Still from a video posted to Youtube.
However, the ice surface impedes this type of movement. The boulder stops bouncing and loses its rotation, presumably because of a weaker, smoother and lower friction surface. The boulder quickly starts to slide, and then follows the slope. This is fortunate for the climbers as the trajectory of the rock markedly changes.
Thanks to loyal reader Dave Eddy for highlighting this amazing video.