‘The forest had gone’: the storm that moved a mountain
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Version 1 of 3. On a small ledge in the Swiss mountains, 200 people were enjoying a summer football tournament. As night fell, they had no idea what was coming In the wake of a natural disaster, certain metrics are used to categorise the event: the buildings destroyed; the cost of repair to the nearest million; a single number for the loss of human life. Yet these figures obscure the truth of such events. They make the outcome seem fixed, somehow proportionate. But disasters are chaotic. Their extreme violence magnifies the consequences of every decision: to stay or to move; to run or to hide. Things could have turned out another way. And how would we talk about them then? In Locarno, Switzerland, on the northern shore of Lake Maggiore, lies the mouth of the Maggia river. Follow it north-west and it winds past sandy, tree-shaded beaches, through rocky gorges and into a broad, glacial valley where, for much of the year, long waterfalls drop down forested mountainsides. Just over 20 kilometres upstream, at the foot of the Pizzo di Brünesc mountain, the river splits in two. This is the upper Maggia valley. To the west runs Val Bavona, with its historic villages of stone-roofed houses. To the east, equally steep and green, is Val Lavizzara. And in the upper reaches of Val Lavizzara, at an altitude of 1,000 metres, is Campo Draione. Campo Draione might be the most beautiful football pitch on Earth – or, at least, in Switzerland. It fills a thin shelf of land above a mountain stream, curtained from the road by forest and surrounded on all sides by peaks blanketed with pines. It was laid in the 1950s, on rubble from nearby hydroelectric projects, and since 1970, for one weekend every year, it hosts one of the most popular events in the Maggia valley: a two-day, eight-a-side football tournament of 18 teams from across the canton of Ticino. Most years, the tournament is on the first weekend in July, but in 2024, it was brought forward, to avoid clashing with a fireworks event in Locarno. So it was on 29 June, a warm Saturday morning, that hundreds of people gathered on and around Campo Draione. There was a family atmosphere; those who weren’t competing were eating ice-cream, buying drinks in a marquee, or swimming in the stream at Piano di Peccia, a village 10 minutes’ walk away, across a narrow car bridge over a deep, green gully. The highlight would take place that evening: a party under the stars with an outdoor stage and lighting rig, three bands and a DJ, stretching into the early hours, when revellers would drift off to tents set up along the edges of the pitch or in farmland nearby. But that morning, the lead organiser of the event, Daniele Rotanzi, kept looking at his phone. The app for MeteoSwiss, the federal weather office, was forecasting a level 3 storm warning – a “significant hazard” – for the canton. “There was certain to be rain,” remembers Rotanzi, an athletic man who looks younger than his 40 years. He consulted the tournament’s 10-person organising committee – all volunteers – and they decided to build a makeshift stage inside the marquee: a 50cm-high wooden platform. Less glamorous, but sensible, they felt, given the situation. The SwissMeteo office for the southern Alps sits on a steep hillside north of the centre of Locarno. From the windows of its forecasting room, the curve of the Maggia delta spreads out below: a giant fan of land pushed some 2.5km into the lake. Few rivers in Europe are as sensitive to rainfall as the Maggia, or swell as fast. Months earlier, in September 2023, the waters had surged 17-fold in a matter of hours; it was the kind of deluge the landscape took in its stride. But at lunchtime on that last Saturday in June, the meteorologists were worried. One week earlier, a thunderstorm in their territory had triggered a debris flow that devastated the hamlet of Sorte, Graubünden. Two people were killed; one was still missing. Sorte was uninhabitable. Now, they saw low pressure moving from France to southern Germany, just as hot air pushed northwards from Italy. In spring 2024, the surface temperature of the Mediterranean had been six degrees above its 30-year average, and in recent days, it had set new records for June. When those currents of hot, wet air collided with the massive concave barrier of the Alps, they would either be deflected or converge and climb, creating the conditions for another major storm. At 13.30, the meteorologists held a video call with police, the fire brigade, the civil protection agency, the transport network and the cantonal experts on hydrology and geology. For the first time in the Ticino canton, they were raising the thunderstorm threat to its highest level: a “severe” hazard, level 4, with risks including flash floods, tree-toppling winds, landslides, giant hailstones and lightning. Radar maps showed heavy rain in the alpine valleys of upper Ticino, and violent thunderstorms in central and southern parts of the canton: Locarno, Bellinzona, Lugano. Warnings went out on local television, radio, social media and the widely used MeteoSwiss app. Police and fire services briefed local command posts. River authorities, forestry districts and municipalities with landslide risks were alerted. But the information was frustratingly imprecise: no one knew where the rain would land. The internal MeteoSwiss weather model was predicting extreme rain over the upper Maggia valley. Yet neither the briefing nor the public warnings specified the risk of flash flooding in the valley: instead, they were general for the whole of Ticino. Thunderstorms are among the most unpredictable phenomena in meteorology, and this was thunderstorm rain. If their model predicts the epicentre of a thunderstorm to within 30km even one time in 10, the MeteoSwiss team are impressed. That is, if it occurs at all. Most MeteoSwiss warnings are based on a 70% chance of the event, but for thunderstorms, that likelihood is almost halved to 40%. As late as Saturday afternoon, the likelihood was that there would be no storm, anywhere in the canton. Daniele Rotanzi is from Piano di Peccia, the village near Campo Draione. About half the people on the pitch were also from the Maggia valley, including Rotanzi’s best friend, Loris Foresti. Foresti was born further down Val Lavizzara, in Prato-Sornico, and the men had known each other since they were four years old. Summers were spent swimming by Piano di Peccia, or at Grotto Pozzasc, a tavern owned by Foresti’s parents beside a shady, turquoise rock pool. Winters revolved around the ice rink at Prato-Sornico. Every year since they were teenagers, the two had taken part in its annual ice hockey tournament. Foresti is a meteorologist, developing software for MeteoSwiss that, among other things, monitors thunderstorms. So when Rotanzi saw that the alert had been raised, he went to his friend for advice. “It was level 4,” says Foresti, “but you don’t know where it is going to hit. I was like – OK, could we do the concert outside after it stops?” There was a strange yellow tint to the partly clouded sky, Saharan dust in the upper atmosphere. On the ground, the air felt close and humid. As the afternoon wore on there were brief showers, but not enough to stop play. And at 6pm, when the last match finished, everyone rushed to the long marquee. The real football was about to begin. The Swiss national team were playing the reigning champions, Italy, in the first knockout stage of the European Championship. The game was projected on to a white sheet, and ribs from the grill were served at trestle tables. Between 300 and 400 people crammed into the tent, their cheers drowning out the growing sound of rain on the plastic roof. By the final whistle, at 8pm, Switzerland had won 2-0 – a historic upset – and it was raining hard, but not enough to dampen the celebrations. There was a rush to the bar. At 9pm, the first band of the night, a spoof “farm metal” outfit, started its set. Outside, a thunderstorm had begun. Much about thunderstorms is unknown. But the biggest puzzle is predicting when and how they will occur, a problem tied to one of the great mysteries of physics: turbulent motion. Light a candle and blow it out. The smoke will rise evenly at first, then start to tumble upwards. That tumbling is turbulence, and in our current understanding of the universe, there is no way to predict the shape it will take. Unlike other phenomena on the frontiers of human knowledge, such as black holes, turbulent motion is something you encounter every day: in the movement of flames in a fire, the path of a fragrance through a room, the rhythm of waves on the shore. When smooth or “laminar” flow breaks up into turbulence, large eddies create ever smaller eddies, with each impacting the movement of the others, becoming exponentially more complex with every passing moment. Turbulent dynamics affect all weather – they are why meteorologists cannot forecast more than 14 days ahead – but thunderstorms especially are formed and governed by turbulent currents. With global heating, the most violent phenomenon in weather may be becoming more violent, and it remains defiantly unpredictable. As midnight approached on Campo Draione, torrential rain had been falling for almost three hours. Inside the marquee, a folk band was playing on the improvised stage. Foresti stood with his back to them, looking out at the downpour, at the mountains lit by a strobe of constant lightning, flickering several times a second. “I love thunderstorms,” Foresti said. “I get excited about them. I took pictures.” As a meteorologist, he knew that this was not just one storm, but a series generated by a stationary front above him, drawing warm, moist air into it “like a thunderstorm machine”. Suddenly, he felt uneasy. The front should have moved. It should be over. “It has to stop now,” Foresti remembers thinking. But the rain kept pouring down. He began to think about the valley, about the people running his parents’ tavern down by the river. He and the hundreds of people around him were in terrible danger. As the band played behind him, Foresti began to shake with fear. When storms come in a series, there are usually lulls between them. But that night, they ran back to back, relentless in their intensity, focused on a strip of land roughly 20km by nine, stretched along the serpentine ridge of peaks, 2,500 metres high, separating the two valleys of the upper Maggia. Outside this area, the rainfall dropped off sharply; in Locarno, almost no rain fell. But by midnight, more than 50mm of rain per hour – 50 litres per square metre – was falling on the ridge. And it landed on snow. Ticino’s climate is hot, almost Mediterranean, and typically any snow would have melted by the end of May. But in 2024, it had snowed so heavily at the end of April that some still lay on the peaks, one month into a hot summer. Snowmelt saturated the ridge, and the rain ran across wet ground. By the time it reached the treeline, it was still 1,000 metres above the villages in the valleys, but the deluge, thick with grit, already had the force to move rocks and snap trees. “A phenomenon as turbulent as a debris flow, combining water with sediment, debris and trees, is impossible to simulate,” says Andrea Salvetti, the canton hydrologist. The water moves, but so does everything it touches: a large rock can change its course; a pile of debris can build a dam. “You can’t know where the water will go.” At quarter past midnight, a woman rushed into the marquee. She had just arrived by car to take her daughter home, and she was terrified. “She said that it was crazy,” says Foresti. “That there were stones jumping on to the bridge, that there were stones below the bridge and they were moving.” “Not everyone wanted to believe it,” remembers Foresti. “Some youngsters said she was talking shit, and she got angry.” But Foresti recognised her description of a debris flow, where “stones float on the mud and the water”. He saw, too, the need to prevent panic. “I was trying to play calm, but I was not calm.” The third band of the night were preparing to start their set, and Rotanzi checked in with the DJ who was driving up to close the party. “What time will you arrive?” wrote Rotanzi at 12.20am. The DJ replied one minute later: “Ciao, I’ll be there in 10 minutes! The roads are horrible. It’s taken me a while.” Rotanzi responded with two thumbs up. Then all the lights went out. Smartphone torches flicked on; rain thundered on the roof. About 200 people stood in the darkness. Someone said they had a generator in a nearby village, and a group went out to pick it up. Then Rotanzi’s phone buzzed. It was the DJ. “The river is overflowing,” he wrote. “I can’t get past.” He sent a photo of water lit by his headlights, pouring across a road. Rotanzi knew the spot; there was no river there. “Turn back,” he wrote, and he called the police. The police said squad cars were on their way, and Rotanzi called the fire chief. “He told me, ‘Keep everyone in the tent.’” There had been flooding and landslides not far away. The group looking for a generator had already left, but came to a stop 50 metres from the bridge. Water was coming over the top of the crossing. They turned back. Inside the marquee, Rotanzi jumped on to a table to address the crowd. There was no way to leave: the road was blocked. Everyone had to stay in the tent. “You could sense that people knew something important was happening,” recalled Rotanzi. “Everyone listened in silence.” Along the ridge between the valleys, the downpour had entered its fourth hour. That night, storm clouds dropped 30bn litres of water. Pure, that water had a weight of 30m tonnes; combined with debris, its mass was inestimable. It tore down trees, drove earth out from under stone and set rocks sliding. The mountains were moving. At a point almost 1,300 metres above sea level, they stopped. A colossal block of stone, packed around with debris, closed off the end of a steep channel. Even after heavy rain, water in the channel had a maximum depth of three metres. Dammed by the rock, the water rose over 30 metres high. Fontana is a historic village of moss-clad stone buildings, built on green terraces in Val Bavona – the opposite side of the ridge from Campo Draione. When the bottleneck burst, Fontana was hit by a blast of water, debris and 300,000 cubic metres of rock. The surge broke walls and shredded cars like they were tissue paper. In its midst, lit by lightning, taller than the houses around it, the colossal 2,000-ton block that had dammed the channel travelled upright on a bed of moving rock, gliding 450 metres from one end of the village to the other. The settlement was sliced in two, buried under a fan of rubble 500 metres long, 500 metres wide and as much as 13 metres deep. Five people lost their lives. Three German holidaymakers had left their house at the top of the village when the bottleneck burst. They were killed in the open; the house survived the storm. At the lower end of the village, a local couple appear to have been sheltering in their home. The building was entirely destroyed. On Campo Draione, the atmosphere had calmed. The tent was unheated, and people huddled together to keep warm under tarpaulins, foil blankets and plastic tablecloths. A lone, battery-powered lamp dangled from the ceiling. Through the gloom, Rotanzi saw a man approaching. It was the stage technician. He seemed agitated. There was something Rotanzi needed to see. Rotanzi stepped out into the rain. Barely five metres from the end of the marquee, where the forest had stood, there was a void. The corner of the outdoor stage jutted into empty space. The wheels of a parked van hung over thin air. He heard the roar of the river, 30 metres below. By his feet, Rotanzi saw the rubble the pitch was built on, exposed by the landslide. In the flashing lightning, it looked like little more than gravel. Rotanzi was stunned. The bridge to the village was blocked. Uphill, through dense, rocky forest, there was a house just 50 metres away. But 200 people would never fit in the house, even if they reached it. Was anywhere safe? The slope above the pitch was steep and high. Who knew what could fall? In the tent behind him, shivering in their wet summer clothes, the partygoers were unaware of the collapse. And Rotanzi realised that he had to make a decision: he could tell them what had happened and risk a panic, or stay silent and risk the entire tent, with hundreds of lives, being pulled into the deluge. In his daily life, Rotanzi is an actuary at an insurance company, used to calculating risk under much calmer conditions. Nothing prepared him for the decisions he had to make that night. He returned to the marquee, found two friends on the organising committee, and brought them out to see. “Nothing was sure that night,” said Rotanzi. “But my main thought was: we can’t allow panic to break out.” Half of the partygoers were not from the area; people had been drinking. If they left the shelter of the tent, hypothermia would set in fast. Rotanzi explained his thinking, and the friends agreed. They would station a security guard at the outside corner of the tent. If he saw any further movement, they would evacuate. But until then, apart from this small group, the landslide should be kept a secret. Inside the marquee, Foresti sensed that something strange was happening. He could hear the river, “and that’s not a place where you typically hear the river, because of the forest”. He had seen Rotanzi and the two friends leave the tent together. He waited a while, then followed. “At the end of the marquee, the forest had gone,” said Foresti. He peered into the darkness with the torch on his smartphone, but its light could not penetrate the rain. He tried to take a picture, but nothing came out. “Then, with the lightning, I saw the river for just one second. When there is a flood the water is turbulent – it’s like a washing machine – but this was much higher and laminar. And it was difficult for my mind to accept. It did not make sense. It was a kind of river that I’d never seen before.” Foresti went to Rotanzi, who asked him to keep quiet. Foresti understood, but shouldn’t they move people away from that end of the marquee? The downpour had gone on for almost six hours. The whole tent could go down. Rotanzi approached people resting at the far end of the marquee, unaware they were next to a precipice, and asked if they might move away from the side. “But without telling them why, I wasn’t very convincing,” he said. “Some people just stayed.” Giorgia Mattei was in the marquee. On the other side of the impassable bridge, in Piano di Peccia, her mother, younger sister and her younger sister’s children were in the house where all three generations lived together. She looked at a picture on the family WhatsApp group of the front door of the house under water. Her younger sister wrote that she was afraid. She wrote that rocks and trees were coming down from the mountain. She and Giorgia’s mother were staying high up; the children were still sleeping. Her mother wrote that the henhouse had been washed away. At 2.30am, Giorgia wrote on the family WhatsApp that they were all alive on Campo Draione; that they were OK. Her younger sister replied that cars were pressing against the side of the house. Her mother wrote that they were all staying together. Giorgia told her mother to stay high up, to stay with her sister. On the other side of the Alps, in the Jura, Giorgia’s father woke up and read the messages on his phone. He wrote on the group chat that he was trying to call and couldn’t get through. But no one read his message. No one could. The family’s phones had all gone dead. The Visletto Bridge over the Maggia had broken in two. The 80-metre stone crossing was the sole transport link to the upper valleys and carried crucial pipes and cables. When it snapped, the upper Maggia valleys were cut off: without telephone signal, internet, running water or electricity. The rain had stopped. There was nothing to do but wait for dawn. In the blue-grey first light, red-and-white mountain rescue helicopters poured up the valleys. At 5am, two hours after the bridge collapsed, the canton chief of police, Commander Matteo Cocchi, had declared a state of emergency. Led by Captain Antonio Ciocco, the police had entered Locarno’s disaster coordination bunker and commandeered a school in Aurigeno to use its football pitch as a helicopter pad. Ciocco demanded assistance from all local agencies – fire, forestry, mountain rescue – and the army. As the helicopters sent back the first aerial images from the disaster zone, the gravity of the situation sank in. There were more than 50 debris flows. Old watercourses had been blasted open. Roads were destroyed. Fontana was almost unrecognisable – its green terraces replaced by a grey lake of rock. “The immediate question was, ‘What is underneath the stone?’” says Ciocco. “Are there injured people? If you can see them, you know they need to be rescued. But what you can’t see, you can only imagine.” Campo Draione appeared on a screen in the command centre. Where the bridge to the village had been, a swath of stone 100 metres wide and four times as long ran from the forest to the river – a quarter of a million tonnes of rock. The landslide by the river was 20 metres wide. The marquee was still there. Up on the pitch, partygoers were emerging into a disordered world. Groups of people stood by the void, staring in disbelief at turf hanging over empty space. Through the hole in the forest they saw Piano di Peccia, half-buried in rubble. A river three times wider than usual coursed through the broken village. When the phones had stopped working, someone had fetched an emergency two-way radio he kept in his car. With its satellite function, they called mountain rescue, who told them to stay where they were. Sitting in cars to warm up, they tried to get news from the radio. FM was down, but DAB worked. “At 6am, we heard someone say that there were 200 people in Campo Draione, and they’re all safe,” remembered Rotanzi. “That was a big relief for many people.” Shortly afterwards, a helicopter landed. Mountain rescue assessed the situation, then left: there were 40 children stranded at a summer camp in Mogno, and they took precedence. The catering team made breakfast. “It wasn’t certain that we could be evacuated that day,” says Rotanzi. “So from 6am, every two hours we told people what we knew.” They had catering supplies, vehicles for shelter and camping equipment, but no way to communicate with family and friends. The partygoers did not know it, but their frantic parents had overwhelmed the police phone line: 500 calls were taken, but 6,000 could not get through. It took until 10am for the police to set up a specialised number. Giorgia Mattei was freezing. She tried to warm up in a friend’s VW camper van, wrapped her feet in aluminium foil, and switched her sodden pumps for a dry pair of army boots, four sizes too large. Her mother, her sister and her sister’s children were just hundreds of metrers away. She did not know if they were alive. At aroundabout 8am, she heard that someone was trying to build a bridge to the village: a farmer who had hailed a helicopter with a laser pen, and come across the landslide to safeguard his cows. Giorgia went to find him, and helped him fell a tree across the torrent. Feet sliding in the borrowed boots, she began to walk across the trunk. “My legs were shaking,” says Giorgia. “I was terrified of falling.” A debris flow from the forest had hit the family home. Giorgia saw the henhouse, 50 metres from its usual spot. The hens were alive. Rubble blocked the house’s front door, and the ground floor was filled with mud. But her mother and younger sister and the children were safe. They had no way of contacting her father. He had driven five hours through the night, believing that his wife, his children and his grandchildren had all been killed. He had attempted, unsuccessfully, to get a lift in a helicopter. He argued with police who tried to stop him. He hitched lifts, and climbed debris flows, going deeper into the disaster zone, as others fled. At 17.30, he reached his broken home, and found his family safe. On Campo Draione, the army had arrived. Evacuees were boarding a Super Puma helicopter, one group of 15 at a time, abandoning tents, instruments, cars. “It is an image that will never leave my mind,” says Rotanzi. “The football pitch is a place for joy, and the contrast with this huge, military helicopter was so big … It was a moment that was great and terrible at the same time.” Rotanzi was on the penultimate helicopter; an eight-minute flight to the school at Aurigeno. From the window, he gazed down at the ravaged landscape, stunned by the scale of destruction. “All night, I had been telling myself, ‘Shit – these people are here because we organised this,’” he says. He felt a wave of relief. Then his phone buzzed. Hundreds of messages. Missed calls. “That’s when I realised what had happened,” says Rotanzi. “We were going back to real life.” The helicopter landed. And he began to cry. No one knows how many people were in the upper Maggia valley that night. The registered population of 1,000 doubles in summer and by the end of Sunday, more than 500 people were missing. It took three full days to go through the list. “There were hundreds,” says Captain Ciocco. “Then 50, then 10. Until, at the end: one person was missing.” The missing person had been on Campo Draione. A 22-year-old local man, he may have left the party before midnight to rest in his car, parked near the bridge. Seven people were confirmed to have died in the disaster: five in Fontana, and two in Prato-Sornico. But though more than 2,200 people participated in the search for the missing man, neither he nor his car have been found. Foresti questions himself: “Did I under-react? There was another level 4 warning some weeks later. There was some hail and that was it.” Given the same information again, he reckons he would not act differently. In public and private, Rotanzi was challenged about his decision not to cancel. “The warning was given for that night,” says Rotanzi. “If we had cancelled at 6pm, the teams would have gone to their tents, in places that were later flooded and hit by rocks. Things could have been even worse.” Should the police have intervened? “We cannot order an evacuation without more specific information from MeteoSwiss,” said Commander Cocchi. But MeteoSwiss cannot provide that specificity – without a scientific breakthrough on turbulent flow, it may never be able to. For all their resources and assiduous monitoring, the Swiss authorities were forced to come to a frightening conclusion: the whole situation could be repeated. There is a visual logic to the mountains; the way trees grow towards the light, the paths of water, eroded over geological timescales. Much of that has been upended. For months, machines worked to clear paths through a moonscape of fallen rock, struggling to undo a few hours of rain. But it will take decades for life to return to the rock, with lichens, then moss, then earth. People who have lived here all their lives – whose grandparents lived here, who knew it as children – are learning the new grammar of a shattered landscape. “I would go fishing behind my parents’ tavern,” says Foresti. “I knew every water pool. It was all a forest, and the river had a completely different path. Now it is filled with stones. Where there was a trail, now there is no trail. Where there was forest and cows would graze, now I can see a mountain. The forest is gone.” The June 2024 flash flood was among the most violent in the region for 200 years. Few expect to wait long until the next. “Such rain events look like they are becoming more frequent,” says Luca Nisi, deputy head of Locarno’s SwissMeteo team. And there are other threats. Almost one year after the Maggia valley storm, the Swiss village of Blatten was obliterated, buried by rock falling on to a glacier, which then collapsed. Melting permafrost appears to have triggered the event, and for the last 10 years, Switzerland’s mean temperatures have been 2.9C above their preindustrial average. Such dangers are not limited to the Alps: last week, in the Italian Dolomites, hundreds were evacuated to escape rockfalls caused by melting permafrost. As Switzerland debates the future of its mountain communities, a retreat from the landscape has a simple appeal. But the climate crisis is a complex problem. By Campo Draione, a mudslide emerged from the forest where there was no natural drainage channel. At its origin stood a cluster of dead trees, killed by a parasitic bark beetle that has thrived in the hotter, drier summers of recent years. Their roots could not hold the ground. Who will monitor the consequences of climate change? The inhabitants of the mountains can be caught off guard, but they have an unteachable understanding of their territory, and the small, consequential ways in which it is changing. Rather than abandon the landscape, it may be time to engage with it more than ever. The football tournament went ahead in 2025. Grotto Pozzasc, the bar owned by Foresti’ parents, is open. The communities are recovering, but they are wounded. “I don’t feel safe when there are thunderstorms,” says Giorgia. “Thunder makes me feel afraid.” That fear may feel new, but it is not unnatural. It is how, until recently, all humans experienced the weather. Not as an inconvenience on an app – predicted, contained – but as a force of nature. For a brief moment in history, we felt that the weather could be tamed. When, all that time, we were making it more wild. This is an edited version of an article first published Das Magazin. Listen to our podcasts here and sign up to the long read weekly email here. |