Storm: National Platform for Natural Hazards

Storms - together with floods and hail - are the natural hazards that repeatedly cause the most property damage in Switzerland each year. Winds with a force of over 75 km/h (or wind force 9) are referred to as storms.

Strong winds cause damage, especially to buildings, infrastructure, vehicles and forests. Storms can cover roofs, tear off parts of facades, uproot trees and whirl around loose objects. Flying debris and falling objects endanger people.

Winter storms in particular, with storm fronts several hundred kilometres long, cause the most damage. Other storm types such as bise, foehn, thunderstorm gusts, tornadoes or downbursts (localised downbursts) are smaller in scale but can also cause massive damage locally.

Winter storms in particular, with storm fronts several hundred kilometres long, cause the most damage

Effects of climate change

Unclear effects of climate change

Windstorm hazard: wind gusts as they can occur every 50 years

Both in Europe and in Switzerland, a trend towards a decrease in winter storms has been observed since the 1990s. However, this observation period is too short to draw any firm conclusions. There is also no reliable information on foehn storms and tornadoes.

NCCS, Effects of climate change

PERILS, Storm catalogue (engl. S. 16-18)

Effective measures

In Switzerland, buildings are generally built to be robust, so that walls only crack in extreme cases. Owners can minimise most medium and minor damage with careful planning and regular maintenance. The federal government also issues behavioural recommendations in the event of storms. Examples of measures include

Technical measures

Plan and implement a safe design for the building structure and envelope (or have it implemented)
Regularly inspect and maintain buildings, facades and roofs

Roof and façade safety

Roof and façade protection

Organisational measures

consistently comply with building standards for the supporting structure, roof, façade and sun protection)
Heed warnings from websites and apps and act accordingly

Chronicle

Devastating storms in the past

1971 Vallée de Joux

A devastating tornado raged on 26 August: the storm in the Vallée de Joux reached wind speeds of up to 300 km/h. The damage was 23 kilometres long and 40 houses were totalled. The damage was 23 kilometres long and 40 houses were totalled. 20 people were injured and 100 were left homeless.

Verwüstung durch Orkan bei Le Brassus und Envy

1990

Between 25 and 27 February, winter storm Vivian swept across large parts of Europe. In Switzerland, it reached top speeds of 160 km/h on the Central Plateau. The damage to forests and buildings was considerable at around CHF 1 billion. Across Europe, 64 people died.

ETH-Bibliothek Zürich, Bildarchiv / Fotograf: Kobi, Hans / Dia_303-32370 / CC BY-SA 4.0

Medel (Lucmagn) GR, Im Westhang Uaul da Curaglia oberhalb Curaglia

1999

On 26 December, winter storm Lothar swept across the Central Plateau with peak gusts of 140 km/h. The total damage amounted to around CHF 1.5 billion (damage to forests and insured property damage at the time).

Lessons learnt from storms Vivian and Lothar

ETH-Bibliothek Zürich, Bildarchiv / Fotograf: Bärtschi, Hans-Peter / SIK_03-097251 / CC BY-SA 4.0

Winterthur, Sturm Lothar 25.12.1999, Schäden

2018

On 2/3 January, winter storm Burglind swept across Europe at speeds of up to 195 km/h. Damage totalling CHF 500 million was caused in Switzerland. The storm combined with the resulting snowmelt led to flooding.

2023

On 24 July, a thunderstorm cell caused violent gusts of wind and severe damage in La Chaux-de-Fonds and Le Locle. The downburst in the Neuchâtel Jura damaged 4,500 buildings, 40 of them severely. The property damage totalled over 100 million francs.

Devastating thunderstorm in La Chaux-de-Fonds