Peterborough Public Health Announces New Harmonized Heat Warning System

Written by admin, June 7, 2016

June 7, 2016 – Heat Warning Information System Now Consistent Across Ontario

Peterborough Public Health announced today, that starting now, it will use the new harmonized heat warning system to make it easier for residents to take precautions from extreme heat wherever they are in Ontario.

“Having a simplified and easier to understand heat warning system is great news for local residents, especially those who are most vulnerable to extreme heat exposure,” said Dr. Rosana Salvaterra, Medical Officer of Health.  “Heat warnings will now be applied consistently across the province so people know when and how to take precautions to protect their health.”

The new heat warning system was developed jointly by Environment and Climate Change Canada, Health Canada, the Ontario Ministry of Health and Long-term Care and Ontario’s Public Health agencies for implementation across the province during the 2016 heat season.

The new heat warning system is based on a combination of the latest in health science, Ontario-specific health evidence, and a detailed analysis of weather patterns in Ontario. The province has been divided into three regions: northern, southern, and extreme south-west (Windsor) area, each with its own updated, region-specific temperature and humidex criteria.

Prior to 2015, there was no consistent approach among Ontario public health agencies for issuing and responding to Heat Warnings to reduce heat-related deaths and illness. Ontario public health agencies used various different criteria for activating heat alerts and response plans. This resulted in a diverse range of thresholds for calling alerts, as well as differing communication protocols and response mechanisms.

Beginning this summer season, Environment and Climate Change Canada will issue Heat Warnings 18 to 24 hours in advance of the heat event. Forecasters will assess if two or more consecutive days of weather that meet either the humidex or temperature criteria (daytime highs or nighttime lows) are expected in the region. If so, a Heat Warning will be issued.

The Ontario Heat Warning Protocol incudes two warning levels:

Level 1: Heat Warning

A  Heat Warning is issued when two consecutive days are forecasted to have a daytime high temperature greater than or equal to 31C AND a nighttime temperature greater than or equal to 20C or a humidex greater than 40.  This level reminds residents of the following core messages: to keep their home cool, stay out of the heat, keep the body cool and hydrated, assist others, and recognize the symptoms of heat exhaustion.

Level 2: Extended Heat Warning

An Extended Heat Warning will be issued for a heat event lasting three or more days.  This level of warning reminds residents of the core messages above, in addition to providing details on how and where to stay cool, advising suspension of strenuous outdoor activities, reminders to assist vulnerable groups, and to watch for further information through the media and the Peterborough Public Health website.

Extreme heat events are a potentially significant health risk and can have a severe impact on the health of vulnerable populations including infants, the elderly, shut-ins, persons with chronic diseases, the morbidly obese and the marginally housed.  Heat related illnesses such as dehydration, heat cramps, heat exhaustion, and heat stroke are preventable.  Most healthy people can tolerate a short period of hot and humid weather as long as they stay cool and drink plenty of fluids. It is important to be aware that some medications may increase the health risks from extreme heat events.


For further information, please contact:

Wanda Tonus
Public Health Inspector
705-743-1000 ext. 285