Above: Photo by Dreerwin/Wikimedia Commons

Aurora borealis, more commonly known as the northern lights, are visible year-round in Canada and Alaska and are typically expected to stay confined to regions of higher latitudes. Yet, from March 23 through March 25, 2023, skywatchers as far south as North Carolina, Virginia and Arizona observed the same streaks of color in their night skies.

Though unusual, this kind of southerly auroral migration will not be an isolated event. The sun oscillates back and forth between periods of activity and inactivity known as solar cycles, which typically last about 11 years from start to end. Solar Cycle 25, which began in 2019, is forecasted to reach its peak — when the sun is most active — sometime in 2025, increasing chances for more frequent and intense auroras in the coming years.

Bright and widespread auroras, like the ones observed at the end of March, are caused by geomagnetic storms originating from the sun. These storms are a result of the sun’s many magnetic fields tangling with themselves. When the fields snap back into place, they release large bursts of charged material from the sun’s atmosphere known as coronal mass ejections. Normally, the Earth is exposed to a regular stream of charged particles from the sun called the solar wind. This “wind” of ions and electrons changes the shape of the Earth’s magnetic field from a spherical shape to a teardrop shape, compressing the field on the side facing the sun. However, in coronal mass ejections, Earth’s magnetic field is impacted with much more force, making the side facing the sun compress more than usual. This increased compression creates an electrical current comprised of moving electrons that collide with oxygen and nitrogen molecules in the upper atmosphere, producing the vivid displays of the northern lights. The stronger the storm, the farther south the auroras can be seen.

However, auroras are not the only result of geomagnetic storms. The sudden surges of magnetic energy from strong storms can also induce currents in electrical grids, causing electrical infrastructure — power lines, power plants and cables — to essentially serve as a giant conductor. This can lead to widespread impacts, from satellite disruptions to radio blackouts and power grid outages. Though the March 23 storm did not damage any critical infrastructure, several past storms have.

For instance, in the 1989 Quebec Blackout, a solar storm compromised the power-generating station, Hydro-Québec, and shut down the Quebec power grid, leaving six million people in the dark for 9 hours. During the 2003 Halloween Storms, a barrage of 17 bursts of charged material from the sun fried transformers — essential components of electric circuits — in South Africa and led to power outages in Sweden. Just last year, a storm knocked out 40 of SpaceX’s Starlink satellites.

However, these events pale in comparison to the 1859 Carrington Event, which had caused auroras to occur as far as the Bahamas. The aurora caused electrical devices, such as the telegraph at the time, to spark and shock their operators.

A storm of that magnitude today would have unprecedented consequences. According to a report from the 2013 Electric Infrastructure Security Summit in London, a Carrington-level storm today would have “the potential for long-term, widespread power outage.” It would also cost an estimated $600 billion to $2.6 trillion. As society continues to become increasingly dependent on electricity, the risk will only increase with time.

This has alarming implications on the North American power grid, which only has five interconnections. Due to how each interconnected region is reliant on shared power lines, a single disruption in one area could have a cascading effect. When a tree branch came into contact with Ohio power lines in 2003, 50 million people in the Northeast U.S. and Canada lost power. In the wake of the Texas winter storms in 2021, nearly half the state faced water disruptions and outages. Additionally, in the 1989 Quebec Blackout, electrical utilities in New England and New York lost significant amounts of power and had to use reserves, even though the blackout itself was limited to the Quebec Province. Clearly, with current infrastructure, electrical malfunctions that otherwise would have remained local are magnified to a national scale.

According to the 2013 Electric Infrastructure Security Summit report, storms similar in magnitude to the one that caused the 1989 Quebec Blackout occur roughly every 50 years, and Carrington-level storms occur every 150 years. As the sun re-enters a period of activity, the risk for a repeat of these scenarios grows once again.

As the report also states, in terms of electrical damage, “the cost of prevention is much smaller than the price of damage a single storm can create.” In 2017, eight U.S. electrical providers built a stockpile of transformers, which are the electrical components most likely to be affected in an emergency. In 2019, Trump signed an executive order to strengthen and increase the resistance of the power grid, which could mitigate any damages caused to infrastructure.

In addition to national preparations, the National Weather Service recommends that each household prepares an emergency kit and an emergency plan — no different than getting ready for a hurricane or another natural disaster. In the end, storms on Earth pose just as much of a threat to the power grid as storms from space — though there is nothing quite like seeing the sky come to life in the process.


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