THE GREAT QUEBEC BLACKOUT: They call it "the day the sun brought darkness." On March 13, 1989, a powerful coronal mass ejection (CME) hit Earth's magnetic field. Ninety seconds later, the Hydro-Québec power grid failed. During the 9 hour blackout that followed, millions of Quebecois found themselves with no light or heat, wondering what was going on?

"It was the biggest geomagnetic storm of the Space Age," says Dr. David Boteler, head of the Space Weather Group at Natural Resources Canada. "March 1989 has become the archetypal disturbance for understanding how solar activity can cause blackouts."

https://imgur.com/QpMEAIP

Above: Sunspot 5395, source of the March 1989 solar storms. From "A 21st Century View of the March 1989 Magnetic Storm" by D. Boteler.

It seems hard to believe now, but in 1989 few people realized solar storms could bring down power grids. The warning bells had been ringing for more than a century, though. In Sept. 1859, a similar CME hit Earth's magnetic field--the infamous "Carrington Event"--sparking a storm twice as strong as March 1989. Electrical currents surged through Victorian-era telegraph wires, in some cases causing sparks and setting telegraph offices on fire. These were the same kind of currents that would bring down Hydro-Québec.

"The March 1989 blackout was a wake-up call for our industry," says Dr. Emanuel Bernabeu of PJM, a regional utility that coordinates the flow of electricity in 13 US states. "Now we take geomagnetically induced currents (GICs) very seriously."

[link to www.spaceweather.com (secure)]

A lot more info in link ^^^