A severe solar storm on Sunday has ignited hopes for a dazzling display of northern lights farther south than usual in the United States and maybe even across Illinois skies.
As the clock ticked away and the sun set in the evening, the storm subsided and chances for a show became slimmer — but did not entirely vanish.
“The progression has been continuing to (weaken), but it’s still elevated. All it takes is a slight change in what we measure, what we look for, that enhanced activity, and then — boom,” said Shawn Dahl, service coordinator for the Space Weather Prediction Center of the National Oceanic and Atmospheric Administration. “So the potential still exists tonight.”
NOAA issued a geomagnetic storm watch Saturday after a coronal mass ejection — a large expulsion of plasma from the sun’s surface — was observed Friday evening. A severe storm like this causes a major disturbance in Earth’s magnetic field. On Sunday morning, it reached a G4 level on NOAA’s scale, from G1 for minor to G5 for extreme.
Also known as aurora borealis, the northern lights are produced when charged particles streaming from the sun collide with Earth’s magnetic field and gas molecules in its atmosphere. The altitude of these collisions, the type of gas molecules and the intensity of the energy determine the aurora’s color, which can include anything from green to pink to blue.
As a storm progresses, geomagnetic activity can fluctuate considerably from periods of escalation to periods of weakening, according to NOAA. The storm’s orientation while it passes over Earth this time around has trended northward. But if it shifts to the south, especially due to elevated solar winds, that activity could escalate quickly. These factors make solar storms and their impacts really hard to forecast, Dahl said.
He has some advice: “Be patient.”
“Sometimes that change can be in a matter of minutes. All of a sudden, you’re building up energy, and then the aurora can suddenly fire up,” he said. “When I talk about being patient, that’s what I’m talking about. And also: Be out there, looking to the north, away from the city lights.”
While this solar storm has the potential to be significant, the initial alert said the prediction center believed it likely wouldn’t reach the intensity of the ones in May 2024, during which the northern lights danced in unlikely skies across the world.
The storm will still be felt into Monday evening, though at a much weaker level, Dahl said.
Solar activity increases and decreases in a long cycle of about 11 years. In 2024, the sun entered the peak of that cycle, known as a solar maximum. But its active stage tends to last several years, Dahl said.
That means chances are favorable for geomagnetic storms that lead to widespread sightings of the northern lights in the near future.
“We certainly think so,” Dahl said. “We’re still in the grips of solar maximum.”
Chicago Tribune’s Rebecca Johnson and Kate Armanini contributed.
