The Col de la Forclaz alpine road pass, linking the popular ski regions around Martigny in Switzerland and Chamonix in France, has been closed due to a rockfall that threatens houses on the Swiss side.
Around 3,500 cubic metres of rubble fell onto the road on Saturday morning. No-one was injured, but several houses were evacuated and rocks fell perilously close to the village of Trient in canton Valais, making the water supply unsafe.
The road is expected to be closed for several days as the authorities clear away the debris. There are also fears of further rockfalls caused by ice expanding in fissures and loosening the rock.
The road is a popular tourist route as it links Swiss ski resorts, such as Verbier, with Chamonix and the Mont Blanc region in France.
The Mont Blanc express railway also connects the regions and remains running.
Rockfalls and landslides have become a persistent threat in Switzerland in the last few years. Last year eight people went missing and have been proclaimed dead following a landslide near Bondo in canton Graubünden. The warming climate has been blamed in large part on the worsening situation.