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Strong geomagnetic storm produces beaming Northern Lights in Northeast

At the Mount Washington Observatory in New Hampshire, the aurora lights were so bright they were easily visible to the naked eye and bright enough before sunrise to walk around the summit without a headlamp. The same strong geomagnetic storm produced neon lights above Alaska.

By Emilee Speck Source FOX Weather

Northern Lights firing off before sunrise in New Hampshire

A timelapse video captured by the Mount Washington Observatory in New Hampshire shows the effects of a strong geomagnetic storm early Tuesday.

A strong geomagnetic storm produced dazzling Northern Lights before sunrise Tuesday in the Northern Tier and lit up the sky in neon green in Alaska.

NOAA's Space Weather Prediction Center (SWPC) said strong geomagnetic storm conditions were observed late Monday night and into Tuesday due to influences from the Sun known as a coronal mass ejection.

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Kp5 and above intensity northern lights (aurora borealis) appear in the sky over autumn trees as it lit up the sky in shades of green in Anchorage, Alaska, United States on September 29, 2025. This natural phenomenon was observed by locals, photographers and tourists. (Hasan Akbas/Anadolu)

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Kp5 and above intensity northern lights (aurora borealis) appear in the sky over autumn trees as it lit up the sky in shades of green in Anchorage, Alaska, United States on September 29, 2025. This natural phenomenon was observed by locals, photographers and tourists.  (Hasan Akbas/Anadolu)

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Kp5 and above intensity northern lights (aurora borealis) appear in the sky over autumn trees as it lit up the sky in shades of green in Anchorage, Alaska, United States on September 29, 2025. This natural phenomenon was observed by locals, photographers and tourists.  (Hasan Akbas/Anadolu)

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Aurora lights seen from the peak of Mount Washington on Tuesday, Sept. 30, 2025.  (Mount Washington Observatory)

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The Northern Lights seen from the National Weather Service in Riverton, Wyoming on Monday, Sept. 29, 2025. (NWS Riverton)

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The Northern Lights seen from the National Weather Service in Riverton, Wyoming on Monday, Sept. 29, 2025. (NWS Riverton)

SWPC Service Coordinator Shawn Dahl said forecasters believe a CME's arrival or "one that clipped Earth" is the cause behind the geomagnetic storm Monday and Tuesday. He said CME effects are ongoing Tuesday, but are expected to weaken throughout the day. 

Strong, Level 3 out of 5, geomagnetic storm conditions were reached about 6 a.m. Tuesday, producing colorful displays of the Aurora Borealis lights in the U.S. The SWPC uses a nine-point scale known as the KP Index to rate geomagnetic storm intensity. Early Tuesday, the KP Index reached 7.33, producing active auroras.

Closer to the poles, aurora chasers and residents in Alaska were treated to an incredibly bright green display of Northern Lights.

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In New Hampshire, at the Mount Washington Observatory, the aurora lights were so bright they were easily visible to the naked eye and bright enough before sunrise to walk around the summit without a headlamp.

The latest solar storm comes less than a week after the launch of NOAA's first dedicated space weather satellite. The Space Weather Follow-On Lagrange 1 satellite will help improve the forecasts the SWPC puts out, and eventually contribute to changes in space weather warnings for industries impacted by solar storms, including the U.S. power grid, GPS, radio and satellite operators.

"This just goes to show the importance of more space weather observations," Dahl said.