Why have the northern lights been so visible? An expert explains

BOSTON – The northern lights have put on a show in 2024. In May, the strongest solar storm in 21 years set off the aurora borealis and on Thursday night, the stunning colors were visible once again even to the naked eye across much of the United States.
Did you miss seeing the spectacular display? Don’t worry, an expert says the conditions that resulted in the recent burst of northern lights activity will be in place for many months to come.
Shawn Dahl, a forecast coordinator with the Space Weather Prediction Center, told CBS Boston executive weather producer Terry Eliasen that the northern lights have been so intense lately because of where the sun is in its 11-year solar cycle. Dahl said that “we are in the midst of solar maximum.”
“What that means is the sun is now this twisted-up mass of strong magnetic fields, and some of these are so localized and intense they reveal themselves as these sunspot groups,” he said. “That’s the source of a bunch of the space weather storms that we’re looking for and predict.”  
Dahl said this solar cycle has been much more active than originally anticipated by an international panel of scientific experts. And this ramped-up activity isn’t slowing down anytime soon.
“We’re in for a ride the rest of this year, all of next year and even into 2026 before things will start to work their way back down to solar minimum,” Dahl said.
What caused the most recent outburst of the northern lights? Dahl said a “pretty significant” coronal mass ejection from the sun hit Earth on Thursday.
“It arrived with a magnetic strength that’s about six times the normal background level that’s out there in space,” he said.
The electrons from the sun interact with the Earth’s magnetic field and collide with various molecules in our atmosphere.
“And because of those interactions eventually light is released. And that light is what we see as the northern lights or the aurora,” Dahl said.
Dahl said CMEs of the level seen Thursday are “concerning” because they can temporarily disrupt radio and power signals. Part of his job is to give advance notice to the satellite community, the North American power grid, the aviation industry and GPS users.
There were even worries about the solar storm interfering with the response to Hurricane Milton, he said.
“With all the hurricane relief efforts going on right now, we had some concern and we’ve been communicating with FEMA and even the White House situation room about the potential of this storm,” he said.
It’s unlikely that the northern lights will put on a similar show Friday, as forecasters say the geomagnetic storm is now subsiding.