The Northern Lights — aurora borealis — light up the night sky east of Denver on Nov. 11, 2025.

Brilliant colors strobed the skies across much of North America — viewed as far south as Florida — on Nov. 11 as a powerful geomagnetic storm arrived in the atmosphere, setting off the auroras.

The Space Weather Prediction Center warned the strong event could affect the power grid or communications and disrupt some GPS signals on Wednesday, Nov. 12, as the event continues. It could also mean another night of dancing colors in the skies over the northern horizon.

Social media feeds quickly filled with colorful photos on Nov. 11 as the sun set.

Geomagnetic storms occur when a coronal mass ejection from the sun's surface arrives in Earth's atmosphere. The ejection that caused the brilliant activity on Nov. 11 erupted from the sun earlier in the week, according to the Space Weather Prediction Center in Boulder, Colorado.

The storm levels in the atmosphere reached G4 – severe – levels at 8:20 p.m. EST on Nov. 11, and the conditions were forecast to continue into the night, said Shawn Dahl, a space weather forecaster at the center.

What causes the 'northern lights'

Coronal mass ejections — an eruption of solar material and strong magnetic fields from sunspot clusters on the sun — occurred on Nov. 9 and Nov. 10, and a solar flare occurred on Nov. 11, the prediction center said.

Auroras can be seen in the south when the sun spews a particularly large coronal mass.

When material arrives at the Earth's atmosphere, it can trigger a geomagnetic storm. One ejection arrived in the atmosphere on Nov. 11.

"We still don't believe the third CME has arrived yet," Dahl said. They expect the third one to arrive around midday on Wednesday, Nov. 12.

The first two "were profoundly stronger than we anticipated," Dahl said. The next one has been the strongest and most energetic of the three ejections, he added.

As for other impacts, Dahl said those who use precision GPS systems should be aware of possible signal degradation. "If you need to be accurate to less than an inch, it could be off by much more than that if this type of activity continues."

Dahl said they'd contacted space launch operations, utility grid officials, and officials at the highest levels of the White House to keep them informed about the situation.

The colors seen over the horizon come from the interaction between incoming solar particles and various types of gas molecules in the atmosphere above the Earth, according to the University Corporation for Atmospheric Research. Interactions with oxygen give off a green and red glow. Nitrogen produces blue and reddish hues.

To spawn the stronger activity, the magnetic field passing over has to be opposite to Earth's magnetic field, Dahl said.

Photos of the lights were posted from Alabama, Arkansas, Florida, Illinois, Massachusetts, Maryland, Oklahoma, South Carolina, Texas, and Minnesota.

Northern lights seen in Florida and across the US

Dinah Voyles Pulver, a national correspondent for USA TODAY, covers climate change, weather, the environment and other news. Reach her at dpulver@usatoday.com or @dinahvp on Bluesky or X or dinahvp.77 on Signal.

This article originally appeared on USA TODAY: Scintillating auroras dazzle in the night sky over North America

Reporting by Dinah Voyles Pulver, USA TODAY / USA TODAY

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