The Swiss village of Blatten has been partially destroyed after a huge chunk of glacier crashed down into the valley.
Although the village had been evacuated some days ago because of fears the Birch glacier was disintegrating, one person has been reported missing, and many homes have been completely flattened.
Local authorities describe the situation as “very bad”, and have requested support from the Swiss army’s disaster relief unit. Members of the Swiss government are on their way to the scene.
The village’s 300 inhabitants had to leave their homes on 19 May after geologists monitoring the area warned that the glacier appeared unstable. Now many of them may never be able to return.
The disaster that has befallen Blatten is the worst nightmare for communities across the Alps.
Climate change is causing the glaciers – frozen rivers of ice – to melt faster and faster, and the permafrost, often described as the glue that holds the high mountains together, is also thawing.
Drone footage showed a large section of the Birch glacier collapsing at about 15:30 (14:30 BST) on Wednesday. The avalanche of mud that swept over Blatten sounded like a deafening roar, as it swept down into the valley leaving an enormous cloud of dust.
Glaciologists monitoring the thaw have warned for years that some alpine towns and villages could be at risk, and Blatten is not even the first to be evacuated.
In eastern Switzerland, residents of the village of Brienz were evacuated two years ago because the mountainside above them was crumbling.
Since then, they have only been permitted to return for short periods.
In 2017, eight hikers were killed, and many homes destroyed, when the biggest landslide in over a century came down close to the village of Bondo.
The most recent report into the condition of Switzerland’s glaciers suggested they could all be gone within a century, if global temperatures could not be kept within a rise of 1.5C above pre-industrial levels, agreed ten years ago by almost 200 countries under the Paris climate accord.
Many climate scientists suggest that target has already been missed, meaning the glacier thaw will continue to accelerate, increasing the risk of flooding and landslides, and threatening more communities like Blatten.