Strong Geomagnetic Storm Sparks Northern Lights Visible Across Northern U.S.

A strong geomagnetic storm driven by increased solar wind from a coronal hole produced vivid Northern Lights across parts of the northern United States late Sunday into Monday, with auroras visible as far south as the Midwest.

The National Oceanic and Atmospheric Administration’s Space Weather Prediction Center (SWPC) issued a Geomagnetic Storm Warning on Sunday when forecasters expected charged particles from the Sun to reach Earth. Early Monday the KP index, a nine-point measure of geomagnetic activity, rose to about 6.67, and storm conditions reached level 3 on the five-point NOAA storm scale, producing active and widespread auroral displays.

Satellite imagery showed a coronal hole — a dark region on the Sun where magnetic field lines open into space — that allowed streams of faster solar wind to flow toward Earth. When those charged particles interacted with Earth’s magnetic field, they energized atoms in the upper atmosphere and produced the green, purple and red light often associated with the Aurora Borealis.

Observers reported bright displays across the northern tier of the U.S., including the Great Lakes, Midwest and Northeast. Cameras at Isle Royale National Park in Michigan captured bright green auroral curtains, while photographers in Alton, New Hampshire, produced nearly hour-long time-lapse sequences of shifting light. In the Pacific Northwest, images and video from the Seattle area also showed visible aurora.

One airline passenger traveling from New York to San Francisco photographed the lights from an airplane window Sunday evening. “Always look out of airplane windows,” Keagan Wernicke wrote on social media after posting the image.

SWPC forecasters said another, weaker display was possible Monday night but that conditions were not expected to match the intensity seen on Sunday. The KP index is commonly used by forecasters and amateur skywatchers to estimate how far from the poles aurora might be visible; values above 5–6 typically produce auroras at mid-latitudes under clear, dark skies.

Geomagnetic storm warnings are issued because stronger storms can affect satellite operations, radio communications and, in extreme cases, power systems at high latitudes. The coronal hole that produced the recent stream of solar wind is a recurring solar feature; such holes and the high-speed streams they generate often lead to short-lived but notable space weather events when they are Earth-facing.

SWPC continues to monitor solar conditions and issues updates and forecasts as new satellite and ground-based observations become available. Skywatchers in appropriately dark locations were advised to check local forecasts and space weather alerts for the latest information on aurora visibility.