
The Aurora Borealis was spotted in a large swath of states, including Idaho, Iowa, Missouri, New Mexico, New York, Oklahoma, South Dakota, Tennessee, Texas and Washington state. Northern lights were visible as far south as parts of Florida and Alabama, a relatively rare occurrence that highlights the severity of this week's storms.
"Well, we had activity tonight — a lot of geomagnetic storm activity," Shawn Dahl, service coordinator at the National Oceanic and Atmospheric Administration's (NOAA) Space Weather Prediction Center, said in a video on X.
A geomagnetic storm happens when charged particles from the sun's atmosphere interact with the Earth's magnetic field. In addition to creating dazzling displays of color, such storms can disrupt technology on Earth, from satellites and GPS to radio communications and the power grid.
Tuesday's activity was the result of a phenomenon called coronal mass ejections (CMEs), massive blasts of plasma and magnetic field from the sun's outer atmosphere that grow in size as they hurtle towards Earth.
Two CMEs arrived on Earth on Tuesday, Dahl said.
The resulting storm reached G4 levels, the second-highest on NOAA's five-step scale, and created a magnetic field that was "not only eight times stronger than what's normal but ... also favorable for continued activity," Dahl said in a later update.
Forecasters are awaiting a third and final CME, which they expect will arrive on Earth at midday Wednesday and be even stronger than the previous two.
"That was the most energetic and strongest of this activity out there in space," Dahl said. "It was traveling significantly faster than these other two, and we think that's going to pack even a stronger punch than what we've already experienced."
The Space Weather Prediction Center says the aurora may become visible "over much of the northern half of the country, and maybe as far south as Alabama to northern California."
The Met Office, the U.K.'s national weather service, says the aurora may also be visible over parts of Britain on Wednesday night, though it is likely to be obscured by cloud cover — as was the case in Michigan on Tuesday.
Luckily, Americans in northern states won't have to wait long for another chance to get a glimpse.




Comment: Just 5 days prior: Powerful geomagnetic storm sparks stunning northern lights across North America