As a heat wave intensifies across Canada, experts are sounding the alarm on a critical secondary threat: strained power grids. According to a federal report, prolonged extreme heat significantly increases electricity demand for cooling, which can trigger local outages.
Professor Jeff Siegel of the University of Toronto explains the mechanism of risk. "When part of the grid goes down, the remaining electricity is routed through the rest of the grid... that increases failure somewhere else because everywhere gets overloaded," he said. This can lead to a "cascading failure" that spreads through the electrical system.
Recent severe thunderstorms following a heat wave caused widespread outages in Ontario and Quebec, affecting thousands. Emergency physician Dr. Edward Xie notes that as more air conditioners turn on, the strain on both the public grid and individual building systems increases.
Experts advise proactive steps. Anabela Bonada of the INTACT Centre on Climate Adaptation recommends closing windows and blinds during the hottest parts of the day and performing annual maintenance on air conditioning units. She also suggests building a DIY air filter using a HEPA filter to maintain indoor air quality.
Health Canada emphasizes that risks are greatest for the elderly, young children, and those with chronic conditions. They recommend preparing emergency kits with food, water, and battery-powered devices, and developing a household plan for extreme heat events.