Using deadwood (on the left) can slow down rockfalls. | Graphic: A. Ringenbach et al. (2023)

Researchers from the Institute for Snow and Avalanche Research (SLF) of the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) in Davos have been rolling over sixty blocks of rock, some of them weighing several tonnes, down the Schraubach ravine in Prättigau in the canton of Graubünden. They documented their speed, their path down the ravine, and where they collided with trees (on the illustration here, orange lines indicate a swift fall, while blue means slow). They found that mountain forest stops flattened chunks of rock (here given in purple) better than rounded chunks (blue). The latter, however, are slowed down well by deadwood in the form of fallen trees (see the graphic on the far left). Field tests such as these can help researchers to predict rockfalls more precisely.

A. Ringenbach et al.: Shape still matters: rockfall interactions with trees and deadwood in a mountain forest uncover a new facet of rock shape dependency. Earth Surface Dynamics (2023)