Extreme heat poses a significant health risk to Canadians. Epidemiological evidence from recent extreme heat events in Canada and internationally has demonstrated a link between heat and excess morbidity and mortality. Heat-related illnesses are largely preventable, given appropriate notification and interventions. However, presently there is no consistent approach in Ontario for issuing heat alerts to reduce heat related mortality and morbidity. As a result, Ontario public health units (PHUs) have chosen different approaches to triggering their heat alerts.
This has resulted in a diverse environment of thresholds for calling alerts, communication protocols and response mechanisms that has been commented as leading to an ineffective use of limited resources and public confusion. PHUs have called for greater consistency in calling heat alerts as well as communicating heat health information across the province, while taking into consideration the diversity of communities across Ontario.
As a result, there is a clear need for a consistent, evidence-based approach to calling heat alerts, while taking into consideration community differences to promote greater PHUs efficiencies and increase the protective reach of heat alerts to communities which may currently lack the resources to independently develop a heat warning and information system. This project has resulted in the development of an efficient, coordinated, evidence-based system comprised of robust, standardized criteria for calling heat alerts and language easily understood by the public as well as the flexibility to address local vulnerabilities and needs.