Solar Storm From Hidden Magnetic Island on the Sun Surprises Scientists

A “secret” magnetic island in a solar coronal hole triggered an unexpected geomagnetic storm in mid-September 2025 (around Sept. 14–15). This very brief but intense G3-level storm was fueled by fast solar wind from a vast, Earth-facing coronal hole on the Sun. Space.com reports that an isolated patch of opposite polarity inside the hole dramatically boosted the storm's strength. NOAA confirmed Earth was struck by a high-speed wind stream from this region, pushing conditions into the “strong” category and sparking brilliant auroras across North America.

Secret magnetic island unleashes a geomagnetic storm

According to NASA, coronal holes are areas where the magnetic field of the Sun extends into space, usually directing a constant solar wind in the direction of Earth. In this instance, however, researchers discovered a tiny "island" of opposite (positive) magnetic polarity embedded in the hole.

According to Dr. Tamitha Skov, a space weather physicist, this positive patch "ended up giving us about 6 hours worth of really intense storming." The surprise storm was fueled by the hidden island, which intensified the effect of the coronal hole and pushed the event into the strong G3 range.

Aurora spectacle lights up US skies

On September 14–15, observers in the northern United States and Canada recorded stunning auroras in shades of green, red, and purple. According to NOAA, the storm caused auroras to be seen as far south as Oregon and Illinois, pushing them down to about 50° geomagnetic latitude (the northern United States).

According to meteorologists, the storm's proximity to the fall equinox enhanced the intensity of the aurora. "Aurora season is upon us, and it's off to a great start," noted meteorologist Scott Sutherland.