In May 2025, this idilic mountainside was turned into a devastating scene. The Swiss village of Blaten was buried by an avalanche of rock and ice. In the Alps, torrential flooding sweeps up trees, mud, and debris. Severe mountain storms are becoming more frequent and more intense. People's livelihoods are increasingly under threat. These days when there's heavy rain, we think, "Uhoh, what's going to happen?" We look towards the mountain tops.

These communities depend on tourism. But more and more often, the unique alpine landscape is unleashing dangerous natural hazards. To keep villages safe, ever larger protective structures are being built. Will it hold this one? this. Oh, definitely. It's like what they build to reinforce highways. But is more infrastructure the answer or will people have to learn to live with the risks. September 2024 in CO in northern Italy's valley people are celebrating Alma, the community's most important holiday.

This year it's especially emotional. Just 3 months earlier, the area was devastated by mudslides. Conor was cut off from the outside world when the road down the valley was swept away. The municipality, population 1,300, lies on the edge of Grand Paradiso National Park. The economy relies on hiking and nature tourism. The festival MC is Joseph Coutano, one of the town's most engaged citizens. He also runs the local civil defense group. At this point, the roads have only been temporarily repaired following the mudslide.

In the space of a few hours, there was about 100 mm of rainfall. A bit farther on here is the water supply. The entire town was cut off for 4 weeks. Hundreds of residents and tourists were evacuated by helicopter. The damage to public infrastructure alone amounted to 30 million. Efforts are now underway to reinstall the water pipes which were completely destroyed. As civil defense officer, Joseph Coutano meets with the head of

the construction company and supervises the rebuilding work. It always feels like a bomb was dropped here. The flood left an enormous crater. You can see the extent of the destruction. There used to be forest here and a crosscountry ski trail. The forest was completely washed away by the flood. The ski trail used to pass beside the house over there. On the edge of the riverbed, the ground around the old water pipe has been churned up.

Right now, there's only a provisional water supply. The pipes can't simply be reinstalled in the same spot. It's an opportunity to rebuild everything in a way that interferes less with nature. So, we're dismantling what was left. And now that the pipes are further from the riverbed, it'll be safer. The town's fresh water supply will now be moved out of reach of any future debris and rock flows.

Natalie Fore runs a nearby Alpine Hotel. A native of Switzerland, she married into a local family and made a life for herself here in northern Italy. I've lived here for 25 years. This is home. My parents are still in Switzerland, but I wouldn't go back. I'm staying here now. The hotel lab has 20 guest rooms. The stone and timber building is typical for the region. It's a family business. The adult children like Cla also work here.

Natalie Fore and her sister-in-law Sylvia will never forget that day three months ago. Out of the blue, the storm broke and the mountain above their heads was set in motion. Suddenly, a lot of water and mud came pouring down and then mud started hitting the windows. We were a bit scared. Straight away, we called our guests and told them to go upstairs to the first floor.

Things could easily have been much worse, but an old farmhouse attached to the hotel acted like a dam. It diverted the torrent of water and debris that was coming down the mountain. This is house. This house protected us. Otherwise, the flood water would have gotten into the hotel for sure.

All the loose material lying up there was swept down. It settled here. It was a mixture of mud, water, and rock. These days when there's heavy rain, we think, "Uhoh, what's going to happen?" We look towards the mountain tops and times are changing. It rains much harder than it used to. When this happened, it had rained for a half a day until the evening. That was enough to cause all this. Unbelievable. For centuries, the hamlets of Ka have existed in harmony with the natural world around them. The locals are careful to preserve this relationship,

especially as the community sees itself as the gateway to the Grand Paradiso National Park. Around 500 km to the northeast outside Gam Parton Kilchin in Germany, Host Hoffman is overseeing the construction of a new type of structure. It's designed to trap fallen trees and other debris during flooding and mudslides. The local water authority wants to protect the popular tourist destination from these types of natural disasters.

Here in the Bavarian Alps, this kind of debris trap hasn't been used until now. So, we did a series of trials together with Boku University in Vienna. We conducted something like 89 different simulations in order to find out where the debris trap would work best. The planning phase also involved an extensive environmental impact assessment. Building here is relatively unproatic because 1.5 million people pass by every tourist season. But in more remote areas, it's more challenging. In some

places, we've debated with conservationists for years about whether we're allowed to build there. They're building a second channel parallel to the stream. In the event of a flood, it will divert fallen trees and other debris into a large basin. There it will be trapped by a great. The stream flows into the famous Parknak Gorge, one of the region's biggest tourist attractions. In 2018, the gorge was blocked by wood, boulders, and other debris during an

extreme storm. When the flood waters broke through the blockage, they swept into the town, killing one person. A nearby sawmill run by the Bow Drexel family was also affected. The local mayor, Elizabeth Kau, witnessed the disaster. The sheer power of nature is unbelievable. Since then, local residents and the mayor herself have been pushing for hazardous spots like this one to be redeveloped.

Usually facilities like Barexel Sawmill are able to both utilize the mountain stream and regulate it. But when the storm hit, there was no controlling the water flow. Tree trunks were coming down. I thought, "What on earth? You're completely powerless. It was a real disaster. It hit the machinery and everything. Normally after something like that, you just close down. Brexel was at the SL gate, but there was nothing he could do. We can feel what's happening. These isolated instances of heavy rain are becoming more frequent and they're causing more and more damage. When there's heavy rain, we're

completely exposed. A key priority of my term as mayor is ensuring safety as much as possible. I want to make that clear. Even if people in the town don't see it because the debris trap is on the other side of the gorge back there, you experience firsthand how much it affects people, how it weighs on their minds, and you see all the damage. There are emotions at play. What we do isn't just engineering. We often manage an emotional response, too. But the solution is both expensive and difficult to achieve. That's because the place where the debris trap needs to be built is deep in the mountains and hard

to access. First, a new road had to be built to reach the spot. The difficulty with this route is that it moves through very unstable terrain. And the slopes are steep, so debris keeps coming down. The old trail down into the valley had been destroyed in the storm. It had to be repaired and heavily reinforced. There's a similar situation in many parts of the Alps. In 2024, the state of Bavaria spent around €7.5 million euros shoring up mountain streams as part of a 30 million euro flood protection package. Months of work was done on

drainage channels and reinforcement structures just so the heavy construction vehicles could reach the actual danger area. This it'll definitely hold. It's like what they build to reinforce highways. I mean obviously if the whole slope gives away again it might slide over but the place itself is secure. Back in Kanye, Italy, Natalie and her sister-in-law Sylvia want to know how their hotel and the neighboring buildings will be protected in the future.

Civil Defense Officer Joseeppe Coutano shows them a makeshift protective wall beyond the remains of the last mudslide. But it's uncertain whether this will be enough. We need to estimate how much material is up there and then raise this wall so that it can withstand everything that might come pouring down. Nature can do whatever it wants here and we have to adapt and respect it. But at the same time, we need to protect human life. If we want to live here, we need protective structures.

Sometimes things like this happen. But it may also be that it happens somewhere else. Hopefully, the severity of that mudslide was just a one-off. It's important that the mountains remain inhabited because when people live sustainably here, then the mountain is alive. In terms of climate change, it is the front line. It's easier to see the effects here than it is in the city. It's like an open air laboratory. We have to observe nature, understand it, and then act. Until now, many people have been blindsided by the effects of severe weather. They need to learn to understand this new threat.

Joseph Coutano has come to meet with the mayor of CO, Franco Alera. The local authorities have commissioned a company to develop a series of simulations. These models show what's likely to occur during future extreme storms. They've just been completed and Franco Alera wants to show them to his civil protection officer and his climate change adviser. Then they'll discuss what needs to be done. We have to understand the power of water. But it is equally important to understand the solid material carried by the torrent in the debris flows.

Anything we rebuild must be done with more consideration for the environment. We have to leave more space because the stream is unique. It deposits a lot of material and it needs room to change course without hitting any structures. Giving nature more space instead of building over it. That's a longestablished strategy in Switzerland.

There early warning systems protect residents and infrastructure from avalanches and mudslides. One of these systems sits above the main road in Gutinin in the Benet Oberland region. It's overseen by mountain guide Alex Schleppy. He knows all about the natural hazards of the alpine region. He's never without his mountain safety gear because he constantly has to check that the warning system on the mountain side is functioning properly. There's a high likelihood that debris will fall through this gully and into the valley below. But it's hard to estimate exactly how much material might come crashing down. So a rope, cable, and a rip cord have

been stretched across it. The system is simple but effective. If the stone hanging a meter above the ground is swept along by an avalanche of debris, it pulls on the rip cord and triggers an alarm. The road is then automatically closed. Local officials and emergency services are alerted and the emergency plan begins. Alex Shreppy is satisfied that the system is functioning properly. I think it's the right way to handle this hazardous spot. The system means we have things under control. After an incident, we analyze what happened. We

work out how much material came down and what has changed. Increasingly, the houses in the valley are under threat from falling rocks and other debris. If another major landslide occurs, experts will have to reassess the risks. Vel Schppy is a carpenter and also the local mayor. He's used to living with the hazards of nature, but it's getting harder. Following the latest risk assessment, the mayor decided that two houses would have to be vacated. These decisions have a big impact. We're talking about people who grew up in these houses, who've lived there their whole lives.

The houses are 300 years old and nothing's ever happened until now. You have to have some difficult conversations. The cost of protecting the houses would have been disproportionately high. So, the residents had to move. The insurance company classified the case as a total loss. All the changes brought about by climate change, like warming and the thawing of the perafrost are happening on a scale that we've never experienced before.

Natural disasters like the Blaten Avalanche are constantly raising new challenges. But despite the immense damage, the early warning systems have saved countless lives. They are a vital way to protect communities in places where it's just not possible to build physical barriers. Back in the mountains above Gish Patton Kilan Holst Hoffman is checking in on the construction of the debris trap. Looks like it's going well. Really well though. Implementing the systems innovative design in this mountainous terrain is not without its challenges.

There were a few difficulties at the beginning. The ground is hard to drill through. We'd prefer to drill through rock than this kind of soft marl, but now everything's going smoothly. Building the debris trap alongside the stream has cost just under €3 million. This route is popular with tourists who pass by after hiking through the partnner gorge. Well, I guess if it's for the safety of the people who live below, it's a good thing. Yeah.

I mean, climate change, we just have to deal with it. It's happening, right? Yeah. Things are getting difficult. Everyone's talking about climate change, and I asked myself, what people are actually doing about it? Is it really necessary to destroy all these bits of nature? Aren't there other measures we could take? European dippers nest in this area, and I think of them whenever I walk through here. Everything's being thrown out of balance. A few kilometers upstream, a warning system is also being built. Holofman is drawing on the expertise of Michelle Klut, professor of landslide research at the Technical University of Munich.

He's developed a system that will be effective in this area. The plan is to use a laser to detect movement on the steep slopes of the gorge, which could trigger a dangerous mudslide. In the case of a landslide, the laser would measure the distance and send an alert. The system uses a normal cell phone network, so we'd get a text message saying that a particular value had changed. We could then coordinate with the officials in charge of the partn gorge and say something like it started to move 6 or 7 cm per day. The laser beam measures the slope with pinpoint accuracy, allowing the system to detect even the most minute change.

This is the current reading from the sensor, and you can see here that it's transmitting, so we're already getting the signal. The new system is similar to one that's already being used in Blaten. We did consider whether we should dam the stream itself. But we worried that the constant maintenance work would be too much for us. This is probably the more economical approach. But it might be smart to look into creating an access point so excavators can get in there. That way, if something happens, we can react quickly.

Ultimately, early warning systems are a very cost-effective approach. We let nature take its course, and when there's no other option, we can intervene on a case-byase basis. Experts are now looking beyond traditional protective structures towards more sustainable ways of keeping people safe. We don't want the Alps to be a builtup area. It should remain in its wild natural state. But safety is an increasing concern and people have increasingly high expectations regarding safety. At the moment, early warning

systems are the only way to tackle the problem. What we need now is a steep learning curve. We need to monitor these processes which can be difficult to understand and we have to get used to the idea that we might get two or three days warning before something happens. Being able to get people to safety in a short amount of time is crucial. Back in Kanye, Italy, it's now nearly a year since the mudslide that destroyed the road into town. The road is passable, but it hasn't been paved yet. The cross country ski trail has been restored because it's really important for winter tourism in Kanya. And the new pumping station for the water supply is also finished.

Around 10 to 15 million euros have been spent on reconstruction efforts here. Mountain communities have to start setting a good example when it comes to sustainable development. We have to prepare for a future that will be completely different to the present. These kinds of natural disasters are occurring more frequently. We need to confront them as a community. People need civil defense training so they know how to act in an emergency. And we have to make our infrastructure as resilient as possible. And if we can, we should build farther away from the mountain streams.

A year after the destruction, hikers are returning to Grand Paradiso National Park. Many are visiting for the first time since the mudslide. The images are still fresh in their minds. We went for a hike, but since the water destroyed everything, we didn't have much choice about what route to take. We didn't expect this much destruction. All the trails are ruined. But it's important to come back so that they can make some money again and so they can bring this beautiful natural area back to life.

It's important to help these people. They're so brave and dedicated. But despite the spectacular scenery, the locals who depend on tourism are worried. People like Natalie Ftori can't shake the fear that the destruction will have a lasting effect on the region. The road isn't very good, not even for walking. Lots of people come by, but there's a lot of dust on the road. It used to be nicer. It may take a while before the effects of the mudslide fade from view. For her daughter, Claire, it's about taking action to ensure that her home has a future.

There have to be changes. In the short term, there should be more protection around us and along the streams. And in the long term, we have to try to treat the environment with more respect. Life goes on. We have to keep moving forward. We'll see how things go year by year. I think it can only get better. Last year wasn't great, but now it is getting better and better. People in the Alps know what it's like to live alongside nature. But increasingly, nature is showing them its destructive side. If this continues,

mountain communities will have to adapt even more and learn to cope with the risks.