Isère

Recorded Natural Hazards (Géorisques)

It has 512 municipalities and 1,298,990 inhabitants. Under the seismic zoning in force since 2011, 161 municipalities are in a medium or high seismicity zone (53% of inhabitants). A natural disaster has been declared 3,393 times since 1982 (one declaration per municipality and decree), mostly for floods (2,254) and storms (512). The most recent was signed on 22 June 2025. 65 municipalities have a high radon potential (category 3), home to 9% of inhabitants. 249 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

• 1982Floods and Mudflows · 6 November 1982512 municipalities
• 1982Storms · 6 November 1982512 municipalities
• 1982Floods and Mudflows · 26 November 1982225 municipalities
• 1983Ground Movements · 30 April 1983199 municipalities
• 1983Floods and Mudflows · 30 April 1983191 municipalities
• 1983Floods and Mudflows · 24 April 1983171 municipalities

Most Frequently Affected Municipalities

• 21Chasse-sur-Rhône
• 19Vienne
• 17Les Côtes-d'Arey
• 17Reventin-Vaugris
• 16Oytier-Saint-Oblas
• 16Roussillon
• 16Saint-Clair-du-Rhône
• 16Salaise-sur-Sanne

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