In the 51-year observation series, the year 2022 ranks among the ten years with the least damage. At CHF 45 million, the damage costs in 2022 are around ten times lower than in 2021. The largest share of the estimated damage costs (around 91 %) was caused by floods, followed by rockfalls and rockslides (4 %), landslides (3 %) and debris flows (2 %). The causes were mainly thunderstorms and heavy precipitation, whereas one tenth of the damage was caused by continuous rain.
Among other things, the long dry phases in 2022 and the absence of major events are responsible for the low cost of damage throughout Switzerland. Nevertheless, major damage occurred locally, for example in Schangnau BE, Zell ZH and Manno TI due to flooding after thunderstorms.
The first severe damage was caused by strong thunderstorms in the Zurich Oberland on 5 May. They brought hail and high rainfall totals. This mainly affected the Töss Valley. In Zell ZH, the Zellerbach torrent carried a lot of driftwood and bedload and flooded the lower part of the village.
The greatest damage occurred on 4 July. Thunderstorm fronts moved across Switzerland during the night and continued throughout the day. Rivers and streams burst their banks in several cantons. The municipality of Schangnau BE was hit the hardest. A violent thunderstorm unleashed in the farthest catchment area of the Emme, causing a flood wave that wreaked havoc in the area of the Kemmeriboden Bad hotel. Within a few minutes, it destroyed the entire basement and ground floor as well as the terrace of the hotel. Fortunately, no persons were injured.
In Kriens LU, too, multiple creeks overflowed their banks and caused major flooding. Apart from private basements and underground garages, a nightclub was affected most severely and suffered total damage. Five million litres of water stood eight metres high in the club.
In the night from 7 to 8 September, considerable amounts of rain fell, especially in the Malcantone region of Ticino. On the right slope of the Vedeggio valley, practically all streams flooded and brought a lot of debris into the valley. This caused considerable damage in the municipalities of Manno, Agno and Bioggio TI, among others.
Rockslide in the Calanca Valley
On the morning of 4 December, around 600 cubic metres of rock fell down the Calanca Valley between Castaneda and Buseno GR. A quarter of this fell onto the Calanca road, blocking it over a length of 150 metres and severely damaging it. The villages at the back of the Calanca Valley remained cut off from the outside world for four and a half days until the road could be used again on one lane.
Collecting data since 1972
The Swiss Federal Institute for Forest, Snow and Landscape Research WSL has been systematically collecting information on storm damage since 1972. The database, compiled with the support of the Federal Office for the Environment FOEN, contains information on damage caused by floods, debris flows and landslides as well as rockfalls and rockslides. Damage as a result of avalanches, snow pressure, earthquakes, lightning, hail and storm winds is not taken into account in the evaluations. The estimation of property, infrastructure, forest and agricultural damage is mainly based on media reports. The data are available to professionals on request and form an important basis for hazard assessment. The survey of storm damage by WSL is used for environmental reporting by the Federal Office for the Environment FOEN.