'Cannibal geomagnetic storm' could create even more vibrant northern lights across America Wednesday

Aurora Borealis spotted across Lower 48

The Northern Lights gave millions of Americans front row seats to a dazzling nighttime spectacle on Tuesday. Janet's Planet CEO Janet Ivey joined FOX Weather to discuss just why so many are seeing these lights:  

Space weather experts are monitoring for the potential of a so-called "cannibal geomagnetic storm" Wednesday, which could produce an even more brilliant display of the Northern Lights which dazzled much of the Lower 48 Tuesday night after that storm reached G4 intensity.

WHAT IS A GEOMAGNETIC STORM?

Vivid Northern Lights displays usually follow a few days after solar events known as coronal mass ejections (CME).  These are massive eruptions of plasma from the Sun’s corona.

Charged particles within that plasma interact with oxygen and nitrogen in Earth's atmosphere, during a disturbance known as a geomagnetic storm, and produce the beautiful colors of the Northern Lights, also known as the aurora borealis.

PHOTOS: STARGAZERS TREATED WITH BREATHTAKING DISPLAY OF NORTHERN LIGHTS ACROSS US

Northern lights dazzle across Lower 48 during G4 geomagnetic storm from strongest solar flare of 2025

The northern lights were spotted Tuesday night as far south as Alabama during a G4 geomagnetic storm caused by the strongest solar flare of 2025. Dr. Steph Yardley, Vice Chancellor Fellow at Northumbria University joined FOX Weather Meteorologist Ari Sarsalari to discuss the rare celestial event.

A so-called "cannibal geomagnetic storm" occurs when a CME travels faster than, and catches up to, a previously released CME, creating an overall more intense geomagnetic storm.

"They all pile up behind each other, so you get this compound effect," Dr. Steph Yardley, Vice Chancellor Fellow at Northumbria University told FOX Weather Meteorologist Ari Sarsalari Tuesday.

7 THINGS TO KNOW ABOUT THE NORTHERN LIGHTS

According to experts at NOAA's Space Weather Prediction Center, the two coronal mass ejections that have already arrived produced Tuesday's brilliant display, but could be outshone by a third CME that is expected to arrive sometime between Wednesday afternoon and evening.

The FOX Forecast Center said the aurora was visible to the naked eye for people as far south as Alabama on Tuesday. Images from Oklahoma sent to FOX Weather showed the northern lights visible through a camera lens.

"Profoundly [stronger] than anticipated," said NOAA Space Weather Forecaster, Shawn Dahl, referring to the two CMEs that have already arrived.

But Dahl said this third CME was the most energetic of the three waves observed in space and significantly faster than the prior two.

"We think that's going to pack an even stronger punch than what we've already experienced."

Northern Lights over Inkster, ND

A bright green aurora of light shining over North Dakota during Tuesday night's Northern Light spectacle

NOAA issued a G4 or greater geomagnetic storm warning through 2:45 p.m. EST on Wednesday.

NOAA has developed a 5-level scale, ranging from G1 to G5, to rate any incoming geomagnetic activity, with G5 being the most intense and rarest kind of geomagnetic storm.

Dahl said these strong geomagnetic storms can interfere with precision GPS systems in addition to potentially causing disruptions to the U.S. electric power grid.

NASA postponed Wednesday's scheduled launch of the Blue Origin spacecraft New Glenn due to the space weather conditions.

THESE ARE THE 5 CATEGORIES THAT MEASURE GEOMAGNETIC STORMS

Despite the anticipated strength of the "cannibal geomagnetic storm," whether the aurora is more visible in America Wednesday will also require some luck, as the Northern Lights are dependent on the magnetic field of the CME aligning in the proper orientation with Earth's magnetosphere.

Even a very strong CME can produce a very weak aurora even if those magnetic fields do not line up properly, making the northern lights a very tricky phenomenon to predict.

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Meanwhile, cloud cover will play the biggest role in aurora viewing.

The FOX Forecast Center expects heavy clouds to cover parts of the Pacific Northwest, while the Northeast will get an opportunity to see the light show after storms made aurora watching difficult Tuesday.

With a clear sky, space weather experts tell FOX Weather that the Northern Lights might even be visible as far south as Florida Wedneday.