Geomagnetic field levels started increasing following the impact of CME produced by the X9.0 solar flare and reached a K-index of 5 (G1 – Minor geomagnetic storm) threshold at 22:41 UTC on October 6. This is thus far the strongest solar flare of Solar Cycle 25.
G2 – Moderate geomagnetic storm (K-index of 6) threshold was reached at 13:34 UTC on October 7, subsiding in periods back to G1 before increasing again to G2 and reaching G3 – Strong levels at 02:42 UTC on October 8.
G3 – Strong geomagnetic storms primarily affect regions poleward at a geomagnetic latitude of 50 degrees.
Geomagnetic storms of this intensity can cause power system voltage irregularities, with the possibility of triggering false alarms on protection devices. Spacecraft systems can experience surface charging, while increased drag on low Earth-orbit satellites and orientation problems are possible.
Navigation systems, including GPS, may face intermittent issues such as loss of lock and increased range errors. High-frequency radio communication can become unreliable and the aurora is often visible as far south as Pennsylvania, Iowa, and Oregon.
Even at G2 levels, aurora spread across more than 20 U.S. states on October 7, including Alaska, Maine, Vermont, Minnesota, North Dakota, Washington, Wisconsin, New York, South Dakota, Idaho, Montana, Wyoming, Pennsylvania, Ohio, Illinois, Virginia, Kentucky, Missouri, Kansas, North Carolina, Mississippi, and California.
A rare display of red auroral pillars was visible low on the northern horizon from the Texas South Plains on the night of October 8. The phenomenon was captured by the National Weather Service in Lubbock around 21:30 LT approximately 24 km (15 miles) northwest of Lubbock.
Here’s a selection of sightings from across the U.S., Canada, and Europe, along with a notable one captured by Matthew Dominick aboard the Dragon Endeavor, which was docked to the front of the International Space Station on October 7, 2024.
Another significant solar flare from Region 3842, this time measuring X2.1 erupted at 19:13 UTC on October 7. This event was followed by a long-duration flare peaking as X1.0 at 20:50 UTC, associated with a large CME off the west limb of the Sun.
While a direct impact on Earth from this CME is unlikely, a minor shock may pass the planet, though little to no geomagnetic activity is expected from this event.
