In March 1989, six million Quebecers lost power for nine hours after a massive solar flare—an explosion of magnetic energy from the sun—created electric ground currents here on Earth, collapsing the power grid. Another geomagnetic storm, in 1921, brought ground currents 10 times as strong. But the fiercest one ever recorded, called the Carrington Event of 1859, electrified telegraph lines—even setting telegraph papers on fire—and created northern lights visible as far south as Cuba and Hawaii. If such a storm were to strike today, the consequences would be devastating. But NASA researchers say severe space weather could be on the way.

Every 11 years, for reasons that aren’t completely understood, our sun hits what’s called its solar maximum: an especially active period when sun spots, solar flares and “coronal mass ejections—these clouds of plasma that flow out of the sun at millions of kilometres an hour,” as astronomer Sten Odenwald puts it, are more likely to occur. The resulting streams of particles and pulses of electromagnetic energy create what’s called space weather, which can have all sorts of impacts here, throwing the Earth’s magnetic field into disarray and disrupting everything from GPS systems to the power grid. We’re now coming out of a quiet period for the sun, as it wakes up and moves toward the next solar maximum, expected in 2013, and experts say we should be preparing for the worst.

If the 1921 storm were to repeat itself today, massive blackouts would affect more than 130 million people, according to a 2009 NASA report on space weather, and over 350 transformers would risk permanent damage. Water distribution would be “affected within several hours; perishable foods and medications lost in 12-24 hours; loss of heating/air conditioning, sewage disposal, phone service, fuel re-supply and so on.” The social and economic impact might last for years. A repeat of the Carrington Event (thought to be at least 50 per cent stronger than the 1921 superstorm) could cripple banking systems, air travel and satellites; in the first year alone, the report warns, it could cost $2 trillion, 20 times more than hurricane Katrina.