Researchers expect more rockfalls at Zugspitze

Researchers expect further rockfalls at the Zugspitze after a large collapse last week on the mountain’s north face, on the border between Tyrol and Germany. Experts plan to monitor the face regularly, ORF reported.

Johannes Leinauer, a slope-movement expert at the Technical University of Munich, said smaller rockfalls ranging from a few cubic metres to tens of thousands of cubic metres were becoming more frequent. He said it was not possible to predict whether or when a much larger collapse might occur.

The team wants to acquire a laser scanner to survey the 2,962-metre mountain’s north face from a distance of four kilometres and track changes. Rockfalls are usually preceded by signs of loosening and visible movement, Leinauer said, sometimes with smaller blocks breaking away first.

The collapse on the Tirol side happened in an inaccessible area last Tuesday. The main fall, shortly before 7 a.m., was preceded and followed by numerous smaller falls, and rock is still crumbling from the slope. The total volume was about 13,800 cubic metres. Leinauer described it as a substantial event, though one of that size occurs at the Zugspitze every few years. Nobody was injured, and no damage to infrastructure was reported.

The rock broke away from an area measuring about 100 by 40 metres, at a height of around 2,800 metres and on a slope of about 80 degrees. Leinauer said this was where researchers expect warm permafrost. In a nearby research tunnel at the same elevation, measurements 15 metres inside the rock have recorded the permafrost warming from minus 1.2 to minus 0.7 degrees since 2007.

Researchers say rising temperatures linked to climate change are thawing the permafrost, which helps hold mountain rock together. Heat takes time to reach deep into the rock, Leinauer said, with a lag of about three months from outside temperatures. Experts expect the greatest warming of the permafrost in the coming months.