Glacier collapses, burying nearly all of Swiss Alpine village

For days, the inhabitants of Blatten, a village in the Swiss Alps, had been warned by geologists that an unstable glacier high above their homes could collapse.

On Wednesday afternoon, days after residents were evacuated, the glacier broke up under the weight of overlying rocks, burying the village under some 3 million cubic meters of ice, rock and mud. Authorities said one person is missing but have not reported any confirmed casualties.

The trail of debris – which officials said stretched more than a mile – blocked the river that flows through the village, flooding the few surviving structures.

“We have lost our village,” Blatten Mayor Matthias Bellwald said at an emotional news conference Wednesday evening, describing the destruction as extensive. He appealed for help to rebuild the village.

Stéphane Ganzer, a councillor for the province of Valais, told Swiss media that the cascade of rubble buried about 90% of the village. Authorities suspect that the collapse was caused by high-altitude snowmelt, but its precise trigger is unclear.

A 64-year-old resident, believed to have been in the area at the time of the collapse, is still missing, police said. In a statement Wednesday afternoon, police said they had deployed a thermal drone and sent rescue specialists to find him.

Debris from the collapse also triggered a dangerous flood. On Thursday, officials in Valais warned that the accumulation of material in the valley had blocked the Lonza River, forming a lake that flooded Blatten’s remaining buildings. Officials have increased the capacity of a downstream dam and evacuated nearby villagers in case water there overflows.

According to Mylène Jacquemart, a glaciologist at the Federal Institute of Technology Zurich, the glacier was crushed and pushed down under the growing weight of overlying rocks.

“The rock slope above the glacier started to crack apart and fall down,” she said in a phone interview Thursday, explaining that rocks had fallen on top of the glacier over two weeks and eventually caused the glacier to give way. “Think of a giant pile of rock on top of a tiny glacier.”

The chain of events that triggered the glacier to dislodge is not yet clear, however. “Whether it was simply the glacier collapsing under the weight of the overlaying material, or additional weight being put on it as maybe more material collapsed from above – we don’t know,” Jacquemart said.

The glacier’s collapse was so explosive that it corresponded to a 3.1-magnitude earthquake on Switzerland’s scale, according to the country’s Seismological Service. In a statement, the agency said the mass movement was one of the largest ever recorded in the country.

Experts are mixed on whether the collapse was caused by climate change. Christophe Lambiel, a geologist at the University of Lausanne, told Switzerland’s national broadcaster that the glacier had previously been supported by a high rock face encased in permafrost, which had degraded over the past 10 to 15 years, putting pressure on the glacier. He said climate change “probably” played some role in the collapse.

Jacquemart said it wasn’t possible to tell without longer-term data, but she said: “The changes ongoing at high mountains are certainly not leading to more-stable configurations. So there’s a possibility that climate change was an important factor, but we cannot say for certain.”

She pointed out that mountains undergo millennia-long cycles of growth and collapse as they strain under geological forces. “Pieces of mountains have to sometimes fall down; otherwise mountains would just grow forever,” she said. “Maybe the time was just right for this mountain to fall down.”