Flood and landslide damage in 2017 cost CHF170 million

Eight hikers were swept away by the Bondo landslide in August never to be found again Keystone

The cost of floods, debris flows, rockfalls and landslides in 2017 was the highest in ten years, according Swiss Federal Institute for Forest, Snow and Landscape Research (WSL). 

However, the amount is significantly less than the inflation-adjusted average of CHF307 million ($322 million) for the years from 1972 to 2016, WSL pointed out on Friday in its annual review. 

About 94% of the estimated damage came from floods or debris flows, while landslides contributed 2% and rockfalls almost 4%. Most of the disasters were caused by thunderstorms and other heavy rainfall (about 66%), 5% by persistent rain and about 29% by other factors or unknown reasons. 

Two events caused most of the damage in 2017: the floods in the Zofingen region in canton Aargau in July and the rock avalanche near the remote village of Bondo in canton Graubünden in August. The latter killed eight hikers when they were buried under 3.1 million cubic metres of crashing rock. Despite extensive searches, the bodies could not be found. This brought the annual death toll caused by such incidents to well above the average of recent years (two to three victims per year).