Yvelines

Recorded Natural Hazards (Géorisques)

It has 259 municipalities and 1,485,086 inhabitants. Under the seismic zoning in force since 2011, its highest seismicity is very low (zone 1 of 5). A natural disaster has been declared 1,915 times since 1982 (one declaration per municipality and decree), mostly for floods (962) and drought (646). The most recent was signed on 18 January 2026. 218 municipalities are covered by an approved natural hazard prevention plan.

Seismicity Zones

Number of municipalities in each zone of the regulatory seismic zoning (from 1, very low, to 5, high).

Natural Disasters Declared Since 1982

Declarations per five-year period.

Most Widespread Events

• 1999Ground Movements · 25 December 1999259 municipalities
• 1999Floods and Mudflows · 25 December 1999259 municipalities
• 2018Drought (Clay Shrinkage) · 1 October 201857 municipalities
• 2016Floods and Mudflows · 28 May 201656 municipalities
• 2016Floods and Mudflows · 28 May 201654 municipalities
• 2022Drought (Clay Shrinkage) · 1 April 202252 municipalities

Most Frequently Affected Municipalities

• 22Saint-Germain-en-Laye
• 19Louveciennes
• 18Chevreuse
• 18Saint-Rémy-lès-Chevreuse
• 17Conflans-Sainte-Honorine
• 16L'Étang-la-Ville
• 16Triel-sur-Seine
• 15Vaux-sur-Seine

Hazards Listed by Municipality

Number of municipalities exposed to each natural hazard according to the departmental major risks file.

Hazards at a specific address on Géorisques