Dozens of people have been evacuated from an Italian ski resort over fears that a chunk of a Mont Blanc glacier could break away after local temperatures soared.
The size of the ice block from the Planpincieux Glacier is around 500,000 cubic metres – the same as Milan’s cathedral, according to Valerio Segor, who directs the local natural risk management service.
"Any fall would be capable of considerable damage and also travel a long way," Mr Segor said.
Roads leading to the popular hiking valley of Val Ferret have been closed and 75 people, mainly tourists, were evacuated after an alert from Stefano Miserocchi, the mayor of nearby Courmayeur.
"The evacuation was urgent and imperative," Mr Miserocchi told reporters. "The situation foresees a high alert in the next 72 hours."
The precarious chunk of ice is located about 2,600 to 2,800 metres above sea level and slowly detaching, Mr Segor said.
"With our monitoring systems and photographic comparisons we have identified a sector of the glacier that is giving way, at a not exaggerated speed," he said.
The thermal shock of high temperatures, which then turned cold before rising again, had made the glacier much more fragile and at greater risk of collapse, he said.
"The water flowing underneath can, in fact, act as a 'slide'. It is the most dangerous situation and one most predisposed to collapse."
Last autumn another section of ice from the Planpincieux Glacier threatened to collapse, prompting road closures in the area.
Mont Blanc is the highest mountain in the Alps at more than 4,800 metres.
