Night skies in many parts of the northern hemisphere are expected to bloom again on Saturday night with the vivid colors of the aurora borealis, or northern lights, as a powerful geomagnetic storm caused by an overactive sun persists through the weekend.
The National Oceanic and Atmospheric Administrationwhich monitors space weather, said in an update Saturday that it continued to observe solar activity that could lead to periods of “Severe-extreme” geomagnetic storms. The federal agency first issued a warning on Friday when bursts of material from the sun’s surface traveled into Earth’s atmosphere, causing irregularities in power, navigation and communication systems.
Major power companies had largely prepared their power grids for the solar storm and their customers were not affected.
For most people, the solar storm was a gift: It sent ribbons of pink, purple and green light across the night skies across much of the United States, Canada and Europe. When the night sky is clear on Saturday, you can expect the lights to appear again.
Known as aurora, the light is caused by particles from the sun interacting with gases in Earth’s atmosphere and is usually only observed at latitudes closer to the North or South Pole. But on Friday night, residents of lower latitudes, including those in North Carolina and Arizona, saw the dancing lights.
Jane Wong, 30, of San Francisco, drove to the Presidio overlooking the Golden Gate Bridge, where conditions started out hazy. But at midnight, her wait paid off when the sky began to clear.
“It’s right here, which is really great,” he said.
Benjamin Williamson, 41, of Bath, Maine, drove to Portland Head Light, a lighthouse in the state. An aurora enthusiast, he had seen the northern lights during another major solar event in 2003 and in Iceland in 2017. Neither of those events, nor the April 8 solar eclipse, prepared him for what he saw on Friday.
“I thought last month’s solar eclipse was the coolest thing I’d ever seen in my life,” he said. “This could have been over him.”
Solar storms are caused by violent ejections of charged particles from the surface of the sun. When headed toward Earth, the material can interact with our planet’s magnetic field, resulting in a geomagnetic storm.
NOAA classifies geomagnetic storms on a “G” scale from 1, or “minor,” to 5, “extreme.” On Thursday, the agency issued its first watch in 19 years for a G4, or “severe,” storm, which was upgraded to a warning Friday afternoon.
The activity has exceeded the agency’s prediction, and some of it is now classified as G5, making it the strongest storm to reach Earth since October 2003.
The storm is caused by a giant group of sunspots, or cold, dark regions of the solar surface with strong magnetic fields. (If you still have your eclipse glasses handy, you may be able to see sunspots during the day.) According to NOAA, the cluster will continue to explode and explode, with effects on Earth at least through the weekend. In 1989, a geomagnetic disturbance disrupted the electrical systems of Canada and the United States. Energy providers have been on guard ever since.
“Utilities have been preparing for a major storm with required vulnerability assessments,” said Bob Arritt, technical executive at the Electric Power Research Institute, an independent research and development organization.
Some utilities saw high temperature alarms going off overnight on parts of the power grid, Arritt said, but he added that it was too early to tell if the alarms were related to the solar storm. He said he could not reveal the location of the alerts until Saturday.
But while the power system faced some additional stress from the storm, he added, “We have no reason to feel there is an imminent threat of damaging the equipment.”
The solar storm prompted managers of several power grids to take extra precautions to keep electricity flowing and to issue warnings to customers about potential outages.
PJM, the manager of the nation’s largest power grid in 13 states from the East Coast to the Midwest, said its geomagnetic disturbance warning would continue through the end of Saturday. ISO New England, which manages the power grid for six northeastern states, issued a cautionary alert notifying participants in wholesale power markets and owners of power generation equipment that abnormal conditions exist in the power system.