One of the world's richest nations is asking what price it's willing to pay to preserve a way of life in the face of climate change.
The landslide that buried Blatten, a village in the Swiss Alps, under 20 million tons of rock and ice was a shocking spectacle, even if it had been predicted almost to the day.
For more than a week, rocks from a crumbling peak of the Kleines Nesthorn mountain had been tumbling down onto the ancient glacier perched above the town.
The ice groaned and cracked under the weight.
Then on Wednesday, May 28, 2025 the Birch Glacier finally collapsed, sending a torrent of debris thundering down the mountainside.
Not in living memory has the Lötschental Valley seen such an awesome display of Mother Nature's cruel power.
Homes that weren't lost under the deluge from above were swallowed by rising waters, as the Lonza River, blocked by the landslide, broke its banks.
For 800 years Blatten had sat in the shadow of the Kleines Nesthorn. In an instant, the mountain had wiped it off the map.
In one sense, at least, the disaster could have been worse.
Nine days earlier, after closely monitoring the mountain's movements, Swiss authorities had ordered the town's 300 or so residents to evacuate to a nearby village.
Only one person, a 64-year-old shepherd who chose to stay behind, perished in the disaster.
But what Blatten has exposed is the precarious future facing Switzerland's alpine villages, as climate change transforms the country's picturesque mountains into an increasingly hostile abode.
Climate scientists warn the Swiss Alps are warming at twice the global average, with temperatures already climbing 2.9 degrees Celsius above pre-industrial times.
Melting glaciers and thawing permafrost are destabilising the mountain range, making catastrophic landslides like the one that wiped out Blatten likely to be more frequent in the future.
While Blatten might be the most dramatic casualty to date, it's by no means alone.
A dozen more villages have already been damaged in similar incidents and, across Switzerland, more than 100 danger zones have been identified.
"The mountains are rapidly changing," says Reto Knutti, one of Switzerland's foremost climate scientists.
The Alps cover about 60 per cent of Switzerland's land mass and most Swiss feel a strong connection to them — not in the least Reto, who grew up in a ski resort in the Bernese Oberland.
"I think the country was kind of in shock when [Blatten] happened," he says.
"Avalanches happen quite often, small rockfalls happen quite often. But the situation where you have a whole glacier, half a mountain coming down? That just doesn't happen.
"I feel we're at the point where we can see clear evidence that climate change is affecting the stability of the Alps overall."
As they wait for their village to be rebuilt, Blatten's former residents are now climate change refugees in one of the world's richest nations.
But even wealthy Switzerland can't hold back the seismic forces shaking the Alps to their core.
"When the mountain falls down, there's nothing you can do," Reto says.
The country is now facing a question with a troubling emotional dimension — what price is it willing to pay to preserve the alpine life that's shaped its national identity?
"In principle, we could afford maintaining certain things for a very long time," Reto says. "The question is whether it makes sense."
Trouble in the heart of the Alps
Hiking through the high Alps is more than just a physical pursuit for glaciologist Matthias Huss.
Each step sparks an intellectual curiosity he's nurtured since he first started walking these trails as a 10-year-old boy.
"Do you feel it?" he says, as the crampons strapped to our shoes crack through the ice.
"It's very special — it's this cold, old ice that has been there for centuries.
"Every time I step on the ice, I have this feeling that I had as a kid when I stepped onto it for the first time."
Back then, in the early 1990s, a huge wall of solid ice at the head of the Rhone Glacier was visible from our vantage point near the car park.
Now there's just a lake, a new feature in a landscape where ice is in rapid retreat. The glacier is another 20 minutes' hike up the trail.
Matthias heads up Switzerland's national glacier monitoring program, GLAMOS, which tracks every glacier in the country.
It's a mandate that's shrinking by the year.
"My work is melting away," he says. "It makes me feel sad."
Glaciers are extremely sensitive to shifts in global temperature and provide one of the most visible demonstrations of the changing climate in the mountains.
Switzerland's glaciers have been particularly badly hit, together losing a quarter of their ice in just the last decade.
The Alps' largest glacier, the Grosser Aletsch, has receded by 3.4km since the 1880s, while the Rhone has lost 1.8km.
Matthias is setting up monitoring equipment for real-time tracking of the glacier's ice volume, but it won't be long before he has to return to move it further up the slope.
"At this place we saw about 8 metres of ice melt vertically [this past summer]," he says. "2025 was bad, but it was not even the most extreme year," he says.
Looking forward 50 years, Matthias says this glacier will have retreated high into the mountains, the white ice sheet in front of us replaced by a bare slope of black and brown.
Wind the clock forward further still and the picture becomes even more grim.
"In a hundred years' time it is quite unlikely that we will still have major glaciers in the Alps," he says.
While retreating glaciers might be the most visible sign of warming in the Alps, what's happening beneath the surface is just as alarming.
Under our feet, a layer of permafrost has been binding these mountains together for centuries.
It's now thawing too, with dramatic consequences for the entire mountain range.
"Permafrost is frozen ground that has stabilised the rocks of this mountain," Matthias explains.
"If the ice underneath the surface is thawing, it doesn't hold the rocks together so efficiently."
As cracks open in the thawing permafrost, water from rain and ice melt can penetrate deeper inside the mountain.
"This can cause pressures within the geological system that strongly accelerate the frequency of rock falls, and so big landslides," Matthias says.
While no single event can be attributed to climate change, disasters such as the one at Blatten are predicted to become more likely in the future as the permafrost thaws.
"The event in Blatten was not the result of just the result of one or two warm years, but it was the result of a long-term rearrangement in these mountains," Matthias says.
Up here the change is incremental, measured in millimetres of melt, in sensors and in satellite data.
But when the balance finally tips it moves all at once, and when it does it reshapes more than just a mountainside.
Entire communities are being forced to confront a new question: not just how to live with the mountains, but whether they can continue to live beneath them at all.
The decision to stay or go
Back down in the Lötschental Valley, excavators scrape over the barren moonscape where Blatten once stood, like tiny specks on a broad sweep of brown earth.
The contours and outlines of the town's former buildings are still etched in Dani Ritler's mind, even if they're now buried deep.
But this new landscape "feels foreign," he says, surveying the site. It's "not real, like a dream."
Dani, a lifelong Blatten resident and local farmer, was down in the valley looking after his sheep the day the mountain came crashing down, swallowing his house, his farmland and the rooms he rented out to tourists.
Since then he's had to live in temporary housing in a nearby village, along with many other Blatten refugees.
The loss Dani feels runs deeper than just physical buildings. In Switzerland, the word for it is "heimat".
"For me, the Lötschental means 'heimat', where I am at home and where I have lived and where I want to live," he says.
"Here there are city people and there are mountain people and for the people who live here, for them this is their 'heimat' here. And they feel free here."
Switzerland is now racing to rebuild Blatten, which authorities hope could be completed as soon as 2029.
But there's no guarantees the town will be immune from trouble in the future.
There's likely to be continued danger of rockfalls in the area with large parts of the municipality deemed high-risk "red zone" areas, where building is not permitted.
Dani says not everyone who fled wants to return to the new Blatten.
"There are people looking to the future and trying to move on," he says. "Then there are some people that are really struggling, that are nearly broken by this situation."
The decision to rebuild Blatten happened almost immediately after the disaster. There was never really any doubt.
Across the country, there was an outpouring of sympathy and support for the townspeople in the wake of the disaster.
"There's a lot of solidarity in this country in the sense that we share the cost of these disasters," Reto says. "But at some point the question is how much can you afford."
Reto still lives in the mountains but makes the daily commute to Zurich.
Even among Switzerland's city dwellers there's a strong emotional attachment to the alpine identity, a mindset Reto has dubbed "Heidi Land" after the children's books set in the Alps of the 1880s.
"It's an idea that we have in our hearts and minds about how Switzerland was 150 years ago," he says. "I feel somehow a lot of people are still living in this land … the reality is it's just no longer the same."
Such ideas are preventing a proper debate about the viability of some alpine settlements, he says.
In the wake of Blatten, Reto believes there should have been a more "serious … not rushed decision on, 'How do you move on from this place?'"
"It's not just that place," he says, "there will be other places in the future."
The total reconstruction of Blatten will cost an estimated $900 million – or $3 million per resident – with about $585 million of that covered by insurance payouts.
That's in addition to Switzerland's ongoing spend on disaster prevention, which Reto says totals about $5.4 billion annually, with roughly $2.2 billion picked up by taxpayers and the rest covered by insurance.
"I don't think we can ignore the fact that's an expensive way of maintaining heritage," he says. "Maybe at some point you just have to say that doesn't make sense anymore."
But, Reto admits, "these are hard conversations because these are conversations about home."
The price of preserving mountain life
One town that did rebuild after a natural disaster is Bondo, a tiny alpine village on the Swiss border with Italy.
In August 2017 millions of cubic metres of rock and mud flowed down into the Bondasca Valley, partially burying the town in a river of brown sludge.
The reconstruction has only just been completed at a cost of almost $100 million — for a village of just 200 residents.
The river channel has been widened with reinforced stone walls, while the town's bridge has been raised several metres.
Huge concrete barriers have also been installed to trap falling rock and debris before it can reach the centre of the village.
Even still, Mayor Fernando Giovanoli admits there's never "100 per cent protection".
"It's designed for what we call a '100-year event,'" he says. "But if a larger collapse happens again, maybe not."
While such significant cost might be unthinkable in other parts of the world, perhaps Switzerland's burden is that it has the means to do it.
Fernando is in little doubt about whether the country should.
"If Switzerland can't [afford it], who in the world can?" he says. "You can't just say we'll leave the valleys. That would be too simple."
Like many Swiss, Fernando is not yet ready to put a price on alpine life, even in the face of an increasingly uncertain future here.
"Talking only about money is not enough," he says. "It's about a lot of things. It's about life. These are our roots."
Watch Switzerland's Crumbling Giants on Foreign Correspondent tonight at 8pm on ABC TV and ABC iview.
