For a decade, the Middlesex-London Health Unit has issued Heat Alerts based on its own Extreme Temperature Alert Protocol. The protocol was developed in response to the provincial government’s 2005 call for regional health units and municipalities to establish response plans for extremely hot days. In an effort to bring consistency to the extreme heat warning systems that resulted from that request, work began a few years ago to develop and pilot a new Provincial Harmonized Heat Alert and Response System (HARS). The system was successfully piloted in several Ontario municipalities and at last summer’s Pan Am Games in Toronto. As a result, the Province has encouraged all health units in Ontario to adopt this harmonized notification system, which has led the Middlesex-London Health Unit to change its process for alerting the community about extreme summer heat.
Therefore, specific extreme temperature alerts will be issued based on the following criteria:
Heat Alerts are issued when one or more of the following criteria are met:
- Environment Canada issues a forecast calling for a day-time high of 31º Celsius or higher for one day, or;
- Environment Canada issues a forecast calling for a Humidex value of 40 or higher for one day.
Heat Warnings are issued when one or more of the following criteria are met:
- Environment Canada issues a forecast calling for a day-time high of 31º Celsius or higher with a minimum day-time low of 20º Celsius or higher for two consecutive days, or;
- Environment Canada issues a forecast calling for a Humidex of 40 or higher for two consecutive days.
Extended Heat Warnings are issued when one or more of these criteria are met:
- Environment Canada issues a forecast calling for a day-time high of 31º Celsius or higher with a minimum day-time low of 20º Celsius or higher for three consecutive days or longer, or;
- Environment Canada issues a forecast calling for a Humidex of 40 or higher for three consecutive days or longer.
These criteria were selected after an extensive review of epidemiological evidence led by Public Health Ontario and Health Canada about the links between temperature and humidity, and health outcomes, including mortality and illness.
The current local forecast does not call for conditions that would trigger heat alerts or warnings. For more information about extreme weather warnings, heat-related illness, and/or humidity visit: http://www.healthunit.com/extreme-heat.
Media Contact:
Dan Flaherty, Communications Manager, Middlesex-London Health Unit, 519-663-5317 ext. 2469
or 519-617-0570 (cell.)
Spokesperson:
Randy Walker, Public Health Inspector, Middlesex-London Health Unit