A fresh mudslide has swept into a remote mountain town in eastern Switzerland where an earlier huge landslip this week dumped rock, rubble and mud metres high and left eight people missing.
In the latest slide, a river of mud poured through tiny Bondo in the eastern Grisons canton, near the Swiss-Italian border, television images showed.
Rescuers continued their search for eight hikers from Switzerland, Austria and Germany reported missing since the initial landslide above the town on Wednesday.
Police in Grisons said the new slide hit in late afternoon on Friday and that some residents who had been allowed to return home had to be evacuated again. Nobody was injured, police said, but the slide smashed equipment that was being used to clear debris from the previous slide.
Melting permafrost from warming temperatures is likely to be one of the factors behind this week's disaster, said Marcia Phillips, group leader for snow and permafrost at the Swiss Federal Institute for Forest, Snow and Landscape Research.
Such a cataclysmic event had probably been in the works for thousands of years as changes in the permafrost, rock structure, water content and pressure above Bondo conspired to destabilise the 3369-metre Piz Cengalo mountain, Ms Phillips said.
"Permafrost was one of several influencing factors, but not the only one influencing this kind of huge event," she told Reuters. "This week was a very large event, exceptionally large."
Smaller but still potentially dangerous slides may become more common as permafrost thaws with rising air temperatures, she said.
After Wednesday's slide, mountain rubble and mud piled up as high as a 15-storey building in places. The initial rockfall kicked off tremors equivalent to a magnitude 3 earthquake, police said.
Helicopters equipped with heat sensors and technology to detect cell phone signals searched for the missing, as did dog teams and teams of 120 people.