Woah, G5 (extreme) geomagnetic storm conditions have been attained due to the recent CME(s) from AR 13664, with solar wind speeds at ~750 km/s and the north–south (Bz) magnetic field component almost reaching –50 nT. Enjoy the aurora show out there! 💫 pic.twitter.com/GAriVKKqnY

If you spot aurora from this major solar storm, you can #DoNASAScience by making a report to participatory science project www.aurorasaurus.org! pic.twitter.com/QF25i6u0SI

According to Hp30 (this is an index like Kp, but it averages over 30 minutes instead of 3 hours), we are in a G5 storm. Anything over "9.0" is G5-- we are at "11". Time will tell if this #solarstorm has the punch to cause Kp to reach G5 as well. #SpinalTap references duly noted. pic.twitter.com/DLCT56Y1F7

The first #solarstorm in this train has hit! The storm is quite fast so the initial impact has caused a G4-level response momentarily. (See the red bar showing Hp30 exceeding 8). The magnetic field is strong and southward, but wildly fluctuating. Expect substorms to cause #aurora… pic.twitter.com/hFV9inK5Gb