Key Points

In mainland France, June and July 2019 were marked by two widespread and intense heat waves. During these two heat waves, for the first time since the implementation of the National Heat Wave Plan (PNC), mainland departments were placed on red alert due to exceptionally high daytime temperatures.

In Normandy, these two heatwave episodes resulted in alert thresholds being exceeded in a single department (Orne) during the first episode in June and in four departments (Eure, Seine-Maritime, Calvados, and Orne) during the second episode in July. During these events, two departments in the region (Eure and Seine-Maritime) were placed under a red alert (for two consecutive days). A significant impact on health was observed during these periods:

• During the periods when alert thresholds were exceeded and for the affected departments in the region, 49 [4–82] excess deaths were estimated, representing a relative excess mortality rate of +9.6%. The heatwave in July was the most intense. People aged 75 and older accounted for the majority of excess deaths (42 deaths) during both episodes.

• Heat-related conditions (defined by the iCanicule indicator, which includes hyperthermia, dehydration, and hyponatremia) accounted for up to 1.6% of emergency room visits and 3.6% of SOS Médecins calls during the first episode. During the second episode, this activity accounted for 2.0% of emergency department visits and 3.0% of SOS Médecins calls. The hospitalization rate following an emergency department visit during these two episodes was 41.2% and 43.2%, respectively. While the impact was greater among those aged 75 and older, all age groups were affected.

The health impacts of the heat observed were not limited to these periods alone, as two-thirds of emergency room visits and SOS Médecins interventions occurred outside of these two heat waves.