Heat waves are Canada’s deadliest form of extreme weather. Do we need better warning systems?

Faculty of Health Sciences
Public heat warnings have often been impugned for not reaching people soon enough, or worse still, deluging them with contradictory advice

Heat waves are the deadliest extreme weather found in Canada, confirmed by the federal disaster database, and the risk it presents only grows. Despite this, public warning systems are still extremely flawed, no reaching people in time or even giving them contradictory advice.

The systems in place are referred to as HARS, being a heat alert and response system, intended to reduce the impact of extreme heat by telling them to drink water and avoid outdoor activity, and to finally warn public officials. Despite this, there were 619 deaths from heat in last year's heat dome.

“We’re really far from being prepared,” said Glen Kenny, a professor at the University of Ottawa who researches heat strain. “And we’re certainly slow on the take when it comes to alerting people.”

It is being worked on, however, with critiques being fixed, and is being adapted differently depending on placement, and is looking for the perfect time to warn people so that it doesn't over-warn people and they start ignoring them.

“Within neighbourhoods, or within regions, you’re going to have a vast difference in temperatures,” Dr. Kenny said. “There’s a few studies that have looked at indoor temperatures, and during a heat wave they can vary dramatically by eight to 10 degrees.” The upshot: Some people might face hazardous conditions well before airport weather stations signal a problem.

Even with a perfect alert system, however, it must be combined with long term measures such as planting trees, as well as the complexities of people without technology or a first language as English or French.

“Certainly the heat alerts are good,” Dr. Kenny said. “I do think they have their limits.”