When the mountain comes - Switzerland's most dramatic Rockfalls and what we can learn from them
- Patrick
- 15 hours ago
- 4 min read
The mountains of Switzerland are majestic, proud - and sometimes deadly. In a landscape shaped by ice, water and time, every peak also harbors the possibility of disaster. Rockfalls and landslides are not just spectacular natural phenomena, they are part of the geological DNA of the Alps. Time and again, the elemental force breaks through - in the past with tragic losses, in the present with new challenges, in the context of a changing climate.
The Alps: a stage for movements
What looks like eternal stability at first glance is actually a delicate balance. The Alps are young, geologically speaking. They grow, work, rub - and sometimes they break. Beneath the surface, forces are at work that no one can stop: Water seeps into cracks, freezes, cracks the rock. Glacier ice retreats, taking the pressure off unstable slopes. The permafrost, the "cement of the mountains", thaws - and entire rock faces lose their hold.
The biggest rockfalls and landslides in Switzerland - a chronicle of disasters
Flims landslide (~7500 BC) - The primal scream of the Alps
Almost 12,000 years ago, a huge mountain thundered into the depths of Flims in the Swiss canton of Graubünden. It was the largest landslide in Europe - 12 billion cubic meters of rock broke loose and buried the Rhine Valley beneath it. The Flims landslide is therefore the largest landslide event and one of the largest known landslides in the world: around 300 times larger than the Goldau landslide and around 1200 times larger than the Elm landslide.
No people lost their lives - they simply weren't there yet. But the landscape was changed forever. The imposing Rhine Gorge, now known as Ruinaulta, was created as a result of this event.
An entire mountain collapsed - and created one of the wildest gorges in Europe.
Plurs (1618) - When a village disappeared from the face of the earth
The proud village of Plurs once stood in the Bregaglia valley, near Chiavenna. After days of rain, the slopes gave way. Around 1,000 people were buried under the rubble. On the evening of September 4, 1618, three to four million cubic meters of rock broke loose and buried Plurs and the neighboring village of Chilano beneath them. The former town can no longer be found today - it was completely wiped out.
A place that disappears from the face of the earth - not because of war, but because of the mountain itself.
Goldau (1806) - The Nagelfluh breaks
On September 2, 1806, a huge mass of Nagelfluh rock thundered down into the valley in Goldau, Canton Schwyz. The Rossberg mountain broke apart after intense rainfall. 40 million cubic meters of debris hurtled down into the valley at 120 km/h, burying four villages and taking people, animals and forests with it. 457 people died.
A tsunami occurred in Lake Lauerz and further destruction followed.
On this day, Switzerland woke up to a new era: the era of conscious natural hazards.
Elm (1881) - A mountain, economically undermined
The village of Elm in the canton of Glarus was shaped - and at the same time weakened - by slate mining in the 19th century. When parts of the slate could no longer hold up in 1881, the slope slid down and 10 million cubic meters of rock buried Elm beneath them. 114 people lost their lives.
A lesson in how human intervention can unbalance nature.
Fidaz (1939) - The silent death
A smaller but tragic event: in Fidaz, near Flims, a rockslide sent 100,000 m³ of material tumbling down into the valley, killing 18 people, including children. The ground had prepared itself silently. Warning signs were not recognized.
The danger is often not loud. It comes insidiously, without warning.
Bondo (2017) - The new reality of mountain hazards
In the summer of 2017, researchers observed unusual movements on Piz Cengalo. Then 3 million m³ of rock, ice and scree tumbled into the valley, taking everything with it - including eight hikers who were never found again.
Thanks to early warning systems, the village was evacuated. But the damage was immense.
The permafrost is thawing. And the mountains are sliding with it.
Brienz/Brinzauls (2023) - When technology saves lives
The village of Brienz/Brinzauls became world-famous in 2023 - not through destruction, but through prevention. Radar measurements showed early on: the mountain was coming. 2 million m³ of material was visibly moving.
The village was evacuated in good time. No one was harmed. A model case for modern natural hazard management.
Blatten (2025) - An event of our time
The last documented rockslide in Switzerland to date: Blatten in Valais was hit by a rockslide in spring 2025, triggered by the Kleine Nesthorn. 3.5 million m³ of rock thundered onto the Birch Glacier. The total volume of ice and rock deposits on the valley floor was estimated at around 10 million m(3).
Impressive Documentation of the rockslide in Blatten:
One person is still missing today. 300 inhabitants had to be evacuated. The rock changed the valley - a new lake was created and the path to the old hut was buried.
Climate change has long been writing its stories on maps.
Why do mountains fall?
The causes can usually be divided into three categories:
Water: Rainfall saturates the rock, frost blows open cracks.
Geology: Porous rock types such as Nagelfluh or slate are unstable.
Climate change: The thawing permafrost acts like pulling a foundation stone - the slope loses its grip.
What do we do about it?
Today, Switzerland is one of the world's leading countries in the field of natural hazard prevention. This includes:
Early warning systems: radar, drones, GPS measurements
Digital twins: simulations of slope movements in real time
Evacuation plans: rapid, coordinated responses to impending events
Public awareness-raising: school projects, hiking warning systems, media
The next landslide will come. The question is not when - but whether we are prepared.
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