Key Points - The Heat Wave Health Alert System (SACS)

The Heat Wave Health Alert System (SACS), established as part of the National Heat Wave Plan, runs from June 1 to August 31. It is coordinated by the InVS at the national level and by the Cire at the regional level. The main objective of this system is to prevent heat from having a significant impact on public health by identifying alert thresholds based on daytime and nighttime temperatures. The monitoring system as a whole relies on the collection and analysis of two types of indicators: biometeorological (IBM) and health-related (mortality, pre-hospital activity, outpatient activity).

As in previous years, the national heat wave plan has three levels:

• Seasonal Watch: June 1 to August 31, 2011

• Warning and Action (MIGA): ongoing or expected heat wave

• Maximum Mobilization: heat wave with consequences extending beyond the health sector

The transition to the Warning and Action (MIGA) level is triggered when both the minimum and maximum IBM values are reached or exceeded on the same day. The IBM (min/max) values represent the average of the minimum and maximum temperatures forecast by Météo-France for the next three days (D, D+1, D+2).The heat waves that occurred during the summers of 2009, 2010, and 2011 confirmed the effectiveness of this mobilization, despite the absence of a major heat wave since 2006.