A massive glacier collapse in the Swiss Alps on Wednesday buried nearly the entire village of Blatten in the canton of Valais under an estimated 3 million cubic meters of rock, ice, and mud, prompting emergency evacuations and raising fears of subsequent flooding from a blocked riverbed. One person, a 64-year-old man, remains missing, local police confirmed.
The partial collapse of the Birch Glacier triggered a landslide so powerful it registered as a magnitude 3.1 event on Switzerland's seismic scale, according to the Swiss Seismological Service. Video footage showed towering clouds of dust and thick brown mud engulfing the village in the Lötschental valley. "We've lost our village," Blatten Mayor Matthias Bellwald stated at a news conference. "The village is under rubble. We will rebuild."
Authorities said roughly 90% of the village had been destroyed. Stéphane Ganzer, a Valais state councillor, told Swiss media that "an unbelievable amount of material thundered down into the valley." The regional government confirmed that the collapse buried parts of the Lonza River, raising the risk of flooding from an accumulating ice-dammed lake. Sixteen residents in two downstream villages were evacuated late Wednesday.
Breaking:
A glacier collapse has buried the Swiss village of Blatten under mud.
The Lonza River is dammed and large parts of the town have been evacuated.
Tragic — but thanks to early warnings from scientists, lives were likely saved.#Switzerland #Blatten #ClimateCrisis… pic.twitter.com/ryxn8NlALL — The Curious Quill (@PleasingRj) May 29, 2025
"There is a serious risk of an ice jam that could flood the valley below," said Antoine Jacquod, a military security official, adding that authorities were working to assess the full extent of the damming. Raphael Mayoraz, a cantonal hazard official, described the blockage as a "mountain" that was steadily growing in volume. "It's like a mountain, and of course, it creates a small lake that gets bigger and bigger," he said.
Cantonal police deployed rescue teams and a thermal drone in search of the missing man, who has not been publicly identified. Officials have also requested assistance from the Swiss Army, including clearing equipment and pumps to stabilize the disaster site. "The deposit ... is not very stable, and debris flow is possible," authorities warned, noting that it remains unsafe for crews to enter the area.
Swiss glaciologist Mylène Jacquemart of the Federal Institute of Technology Zurich said in an interview that the event was likely triggered by the growing weight of overlying rocks. "Think of a giant pile of rock on top of a tiny glacier," she said. "The rock slope above the glacier started to crack apart and fall down." She emphasized that the exact sequence remains unclear: "Whether it was simply the glacier collapsing under the weight of the overlaying material, or additional weight being put on it... we don't know."
The incident follows growing concern among experts over the impact of climate change on glacial stability in the Alps. Christophe Lambiel, a geologist at the University of Lausanne, told Swiss broadcaster RTS that climate change "probably" played some role, citing long-term degradation of the permafrost supporting the glacier's rock face.
Switzerland, home to more glaciers than any other country in Europe, lost 4% of its total glacier volume in 2023 and 6% the year before, marking the two most significant annual declines on record. The disaster in Blatten comes just days after the bodies of five skiers were recovered from a glacier near Zermatt.
