Key Points

• The summer of 2021 was marked by a mild heat wave in southeastern France in August and short-lived, localized exceedances in June and July. Nine departments were affected by these episodes, representing 12% of the metropolitan population. Among them, three are located in the region: Drôme, Isère, and Rhône.

• In Auvergne-Rhône-Alpes, a heatwave in August (August 11–15) led to exceedances of alert thresholds in three departments of the region (Drôme, Isère, and Rhône), while the departments of Ardèche and Drôme were under an orange alert during this period. A significant impact on health was observed during the period when alert thresholds were exceeded and in the affected departments of the region:

  • 85 [66–120] excess deaths were estimated, representing a relative excess mortality rate of +19.2%. The age group accounting for the majority of excess deaths (70 deaths) was those aged 75 and older.

  • Heat-related conditions (defined by the iCanicule indicator, which includes hyperthermia, dehydration, and hyponatremia) accounted for up to 0.4% of emergency room visits and 1.0% of SOS Médecins calls during the episode. The hospitalization rate following an emergency department visit during this episode was 67%. While the impact was greater among those aged 75 and older, all age groups were affected.

These results underscore the importance of anticipating the impact of heat throughout the summer and in advance of heat waves, even when these are short and mild. They reinforce the need for enhanced measures during heat waves and for tailored prevention efforts targeting the most vulnerable as well as the general population.

• For more information: National Heat Wave Public Health Bulletin