Thousands of tonnes of rock break off summit of Austrian mountain

Geologists blame melting snow and thawing permafrost for incident on Fluchthorn mountain near Swiss border

Thousands of tonnes of rock have broken off the summit of a mountain popular with climbers and tumbled into a valley in Austria in an incident blamed by geologists on melting snow and thawing permafrost.

The incident on the Fluchthorn massif, part of the Silvretta Alps in the state of Tirol close to the Swiss border, led to a huge volume of black and grey rocks cascading down the mountain, and created clouds of thick dust visible for miles around, before much of the debris was carried away by a river, authorities said.