Researchers place Zugspitze rockslide in permafrost zone

Researchers say a rockslide on the Zugspitze occurred in the mountain’s permafrost zone, according to BR, which reported new findings from drone surveys and other measurements.

The rockslide happened on September 22 on the mountain’s Tyrolean north face, at about 2,800 metres above sea level. The 2,962-metre mountain’s steep, inaccessible terrain complicated the investigation. The collapse continued throughout the day and raised a dust cloud visible from far away.

Researchers from the Technical University of Munich’s Chair of Slope Movements estimate that about 13,800 cubic metres of rock fell. The scar is around 100 metres high and 40 metres wide, with a collapse face covering about 4,000 square metres and sloping at roughly 80 degrees.

The altitude corresponds to the local edge of permafrost in the Zugspitze massif. Permafrost is ground that remains frozen year-round; ice in cracks and fissures can affect rock stability as temperatures change and the ice thaws.

Researchers found visible ice in parts of the break and used an infrared camera to examine the scar, which appeared very cold. They are still analysing temperature data. Measurements in the nearby Kammstollen tunnel, a few hundred metres away at roughly the same height, show a rock temperature of minus 0.7 degrees Celsius.

Michael Krautblatter, a professor at the TUM chair, said the summer heat wave is only now reaching depths of several metres in the rock. It takes time for warmth to spread through the stone, he said.

The team plans to install a laser scanner to monitor a four-kilometre-wide stretch of the Zugspitze’s north face and provide warning of further rockfalls. Researchers will also continue analysing seismic measurements, drone images and temperature data to understand how the affected section may develop.