The destructive landslide in the Swiss village of Blatten is the latest natural disaster to hit valley communities in the Alpine nation.
While Blatten was engulfed by a slick of icy sediment this week, early warnings of a potential landslide gave residents time to evacuate. — who chose to remain in his home — is currently unaccounted for. The search for him has been suspended.
is an early warning success story.
Government agencies there use a broad range of technologies and methods to assess risks that could threaten lives and property.
This includes terrain mapping and continuous monitoring of rainfall, permafrost melt, groundwater levels, tectonic shifts and ground movement.
This data allows authorities to maintain hazard risk maps across the country.
“Every community in Switzerland that’s affected by a hazard has a hazard map. They’re federally mandated for the areas where people live,” said Brian McArdell, a geomorphologist at the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL).
In Blatten’s case, officials issued alerts after a nearby rockfall destabilized the Birch Glacier.
Combined with warming summer temperatures, the glacier fractured. A slurry of ice, sediment and mud then roared down the mountain to the village below.
“When you slam rock over ice, what you do is liquefy part of the ice,” Daniel Farinotti, a glaciologist at ETH Zurich, told DW. “The ice melts, and that lubricates whatever you have.”
The Blatten landslide was particularly rare.
“The sheer size, the amount of material that has been moved there, that’s not something you see every day, not every year, not every decade in Switzerland,” said Farinotti. “It’s kind of a historic event.”
World’s mountainous regions most at risk
Steep slopes, unstable terrain and exposure to high rainfall or permafrost melt put mountain regions more at risk of landslides and avalanches.
For valley communities in Switzerland, the potential for a landslide can mean entire towns need to be evacuated.
Following the Blatten landslide, several nearby communities , including for
Brienz, a village around 25 miles (41 km) north of Blatten, is also preparing for possible evacuation. The town has faced and “near miss” rockslide events since 2023.
“In general, debris flow is a mixture of coarse and fine sediment — so everything from boulders, to mud, to very fine sediments and water,” said McArdell.
“These events can occur quite suddenly and they’re quite, quite dangerous.”
Regions with the highest landslide-related fatalities globally include the Himalayas, parts of Central and South America, Italy and Iran.
Predicting landslides remains a challenge
While landslides can be forecast, predictions tend to be “probabilistic” rather than precise, Fausto Guzzetti, a now-retired geomorphologist formerly with Italy’s Institute for Applied Mathematics and Information Technologies (IMATI), told DW.
“We can predict in [a] general area, it could be in a municipality, it can be a catchment,” Guzzetti said.
Unlike earthquakes and floods, monitoring landslides is far more difficult.
While earth tremors can be registered using seismic instruments, and floods can be quickly detected visually, most landslides are unnoticed.
“Tens of thousands of landslides simply go unreported,” Guzzetti added. “We don’t know where they are, and this complicates the ability to forecast them.”
Even small slides — just a few meters in length — can be deadly, especially if they carry large debris or occur near homes or roads. “A cobble that hits a car or hits a person walking along a road can kill,” said Guzzetti, “That’s significant.”
Climate change is also expected to increase rainfall in mountain regions, which in turn is predicted to cause more frequent small-scale landslides.
Global call for action
Efforts are being made to strengthen international monitoring and preparedness for landslides and .
The International Conference on Glaciers’ Preservation is currently being held in Tajikistan, where Farinotti expects the release of a “Glacier Declaration” urging greater action to protect ice masses from the effects of climate change.
“[It will] call for various actions and, among others, it will call for increased preparedness against risk deriving from cryospheric hazards, so avalanches,” he said.
Guzzetti also highlighted the UN’s Early Warnings for All initiative, which aims to establish a global early warning system by 2027. If achieved, this could be a major step toward saving lives from natural hazards.
While wealthy nations like Switzerland have reliable infrastructure to warn communities of potential disasters, many others are still playing catch-up. According to UN figures, only 108 countries had the capacity for “multi-hazard early warning systems” last year though that is more than double the number from 2015.
The benefits are clear, said Guzzetti, pointing to the Blatten evacuation: “It seems that they were very good at evacuating the town in time, so that fatalities were nil, or very small.”
“I think it points to the fact that we are moving in the right direction.”
Edited by: J. Wingard
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