Thursday 24 August 2017

Eight missing after landslide in Graubünden, Switzerland.

Eight people are still missing after a landslide swept through the village of Bondo in the Swiss canton of Graubünden on Wednesday 23 August 2017.  The event occurred at about 7.30 am local time, when abut 4 million cubic meters of mud and rock swept through the village, covering a stretch of land about 5 km in length with a thick layer of debris, and resulting in the population of the village being temporarily evacuated, in many cases by helicopter. The eight missing persons are said to include Swiss, German, and Austrian nationals. Six other people who were initially reported missing have been found alive and well in neighbouring Italy, where they had travelled for the day.

Road covered by debris following a landslide in Bondo, Switzerland, on 23 August 2017. EPA.

Major landslides are a common problem in Graubünden, and are generally associated with Alpine lakes overflowing following periods of heavy rain. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. Consequently many areas, including Bondo, have early warning systems in place, designed to detect these events and allow people to evacuate before landslides hit. However the suddenness and severity of this weeks event appears to have caught local authorities by surprise, with people subsequently being caught in the path of the landslip.

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