Geologists say the Piz Cengalo mountain on the Swiss-Italian border, which collapsed last week causing a huge landslide in the Swiss village of Bondo, remains unstable. The dangers are preventing locals from returning and are hindering the clean-up operation.
The residents of the remote mountain village of Bondo in the Val Badosca in canton Graubünden must remain patient before returning to their homes. Experts told Swiss public television, SRF, on Sunday that the dangers of further rock- and mudslides are too great. Cantonal and federal specialists warn that another million cubic meters of rock from the Piz Cengalo are slowly moving and that a massive rockfall is possible.
Geologists flew over the site in a helicopter at the weekend to inspect the 3,369-metre mountain using lasers and other measuring equipment. However, they were unable to get close due to falling rocks.
On August 23, four million cubic metres (140 million cubic feet) of rock came crashing down the mountain, resulting in a huge landslide that partly buried the small village of Bondo, near the Italian border.
On Saturday, Swiss officials called off a search by over 100 rescue workers for eight people missing since the landslide struck, acknowledging they were likely to be buried under millions of tons of rock. Search operations stopped following a second landslide at around 4:30pm on Friday. All the victims were hikers: Two Swiss, four Germans and two Austrians.
Austria’s foreign ministry said a married Austrian couple were among those unaccounted for. No children or locals from the region were among those reported missing.
After the original landslide on Wednesday, buildings were damaged and a trail of destruction was left by a river of mud and stone. One hundred Bondo residents were evacuated as a precaution. Hikers from nearby huts were also airlifted after rocks and mud hit the area. A separate group of six people also reported missing were later located unharmed in Italy.
On Sunday, Graubünden police announced that they had opened an enquiry into whether the hikers had been sufficiently warned against the known risks. According to media reports, the local authorities had installed signs on footpaths warning about the risks of rockfalls. At least one path had been closed. Letters had also been sent to property owners in the Val Badosca to alert them to the dangers and a ban had been imposed in certain areas to prevent owners from accessing their properties.
It is believed the event was caused by a combination of thawing permafrost and water pressure dislodging rocks.
The authorities were alerted by an automatic alarm system that had been set up in the region after a massive landslide in 2012 down Piz Cengalo. In 2013, 60% of locals voted in favour of spending CHF4.5 million ($4.7 million) on a flood prevention project that involved relocating a campground, widening the riverbed and building a concrete wall to shield the village.