A powerful solar storm, identified as a "cannibal CME," impacted Earth's magnetic field on September 1, 2025, resulting in spectacular auroral displays visible across Europe and North America.
The event reached G2 (moderate) geomagnetic storm levels. It originated from an M2.7 solar flare on August 30, 2025, associated with sunspot 4204. Upon arrival, the solar storm caused solar wind speeds to surge past 670 km/s, with the interplanetary magnetic field strengthening to between 20-26 nanotesla. However, the storm's intensity was somewhat limited by the predominantly northward orientation of the interplanetary magnetic field (Bz).
Observers reported vivid auroral phenomena from Scotland to the northern United States. Stevo Howells in Scotland described the event as "Wow, the sky just lit up pink and green." Julie Winn in Northumberland, England, witnessed the northern lights over Whittledene Ponds, calling it a "wonderful visual eyeball." Photographer Paul Appleby documented the display at St. Mary's Lighthouse in Whitley Bay, England, marking it as "the first one of the season in the bag."
In France, Alexis Linant observed the auroras above Puy de Dôme, noting, "too bad, it was starting off pretty well!" Across the Atlantic, Canadians also enjoyed the spectacle, with Jamie capturing a stunning timelapse of the northern lights over Grand Bend, Ontario. In the United States, Greg Gage in West Virginia reported, "Labor Day ended with an auroral display here." Leah Howard experienced an "extraordinary view" of the aurora during a flight south of Pittsburgh, Pennsylvania. Photographer Alex Resel noted, "Weak aurora northeast of Tower City, North Dakota now," while aurora chaser Igor Arkadiev commented, "Despite the highly anticipated CME being a letdown with mostly positive Bz, the brief early-night display was still a joy to watch."
This event highlights the complex interaction between solar activity and Earth's magnetosphere. A "cannibal CME" occurs when one coronal mass ejection overtakes another, potentially creating more powerful solar wind disturbances. While the magnetic field's orientation influenced this event's intensity, it still provided a memorable celestial display, underscoring the ongoing solar maximum phase, which is expected to continue for several more years.
Experts also noted that the September equinox, occurring on September 22, often correlates with increased geomagnetic activity due to Earth's alignment with the sun, suggesting that further displays could be anticipated.