20 years ago: Massive blackout sends Mississauga and much of Ontario into darkness


Published August 14, 2023 at 12:35 pm


It was about 6 p.m. on a late summer Thursday in 2003, and Square One Shopping Centre and its surroundings–including a usually bustling Living Arts Centre and the area outside City Hall–resembled a ghost town.

Nearly two hours earlier, on Aug. 14, 2003, at about 4:10 p.m., something went catastrophically wrong down in Ohio when overloaded transmission lines sagged into foliage.

And then the power went out. In many places. In two countries.

It would later be revealed that a software bug in the alarm system operated by First Energy, a company headquartered in Akron, Ohio, left plant operators unaware of the transmission line issue on that Aug. 14 afternoon and subsequent need to redistribute load immediately.

So, what should have been a manageable local blackout, according to officials and experts who delved into the massive and historic power outage in its aftermath, “cascaded into the collapse of much of the Northeast regional electricity distribution system.”

In the history of “oopses”, this one ranks right up there.

Starting just after the clocks turned 4:10 p.m., the power went out in Ohio and the cascade effect quickly plunged other parts of the U.S. midwest, much of the U.S. northeast (eight U.S. states in all) and most parts of Ontario into darkness.

While many places, including parts of Mississauga, had power restored in a matter of several to seven hours, other locations were in the dark for several days and some areas for nearly a week.

Full power was brought back to parts of Toronto and New York City two days later, on Aug. 16.

The massive outage affected some 50 to 55 million people, including an estimated 10 million in southern and central Ontario, at the time making it the world’s second-most widespread blackout in history (the 1999 southern Brazil blackout ranked No. 1).

Two decades later, improvements have been made to the way in which people in Canada and the U.S. receive their power. But the system is still vulnerable to failure, either by accident or cyberattack.

In recognition of Emergency Preparedness Week in Canada in May, City of Mississauga officials are urging people to be prepared for such widespread power outages or other kinds of emergencies and disasters that can strike at any time.

Nobody ever thinks that a widespread emergency or natural disaster is just around the corner. But it could be, and Mississauga officials want people to be prepared.

“Mississauga wants to remind residents about the importance of emergency planning. Mississauga has a history of widespread emergencies, including the 1979 train derailment, 2003 blackout, 2016 Hickory Drive explosion, COVID-19 and more,” City officials said in a news release.

“Emergencies don’t always come with a warning, but there are ways residents can be proactive by taking concrete actions to better protect themselves, families and pets.”

For more information about emergency preparedness, read Mississauga’s Emergency Preparedness Guide.

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