The rocks fell from Piz Cengalo in Val Bondasca, a valley close to the village.
POLICE say as many as 14 people are missing after a dramatic landslide in Switzerland, which was caught on camera.
Around 100 people have been evacuated from several small villages in the Val Bondasca region following the landslide which occurred on Wednesday.
Police said 12 farm buildings, including barns and stables, had been destroyed, while Graubunden's main southern highway was closed to traffic.
Mittner described the missing people as "Alpinists and walkers". Thanks to the alarm system's signal, before the debris approached the village of Bondo the fire service was able to evacuate its inhabitants.
The landslide occured near the Italian border.
Mittner said Bondo would remain sealed off until at least Friday morning.
"People are immediately gone, leaving everything behind them". Nearly four million cubic metres of rock were detached, or the equivalent of 4,000 single-family houses. "It is not known how long they will have to stay outside the home, because at the moment there is neither water, nor electricity in the village of Bondo", said Ms. Rauch.
Police said the landslide struck a remote valley in the south-east of the country yesterday. Villages were equipped with an automatic alarm system after a massive rock fall in 2012. Among these eight, two are Swiss, two are Austrian and four are German.