Magnetic storm on 10-12 May 2024

A magnetic storm, the strongest one for the last 20 years, began at about 17:00 UT on 10 May 2024. According to Space Weather Scale, the storm had the highest G5 class (extreme) during two days. Development of this unique event according to the results of magnetic field monitoring at IKIR FEB RAS observatories is illustrated in the figures.

It is clear that field variations during the storm are one order and more higher than calm field variations and increase very rapidly with latitude. The source of these disturbances is the Sun. On 7 May, the active region AR 3664 on the Sun grew in size (up to 15 Earth’s diameters, it became close in size to the known Karrington spot that caused the strongest magnetic storm ever observed in 1859) and got a complex magnetic structure promoting the formation of solar flares. As the result X-ray flare series, accompanied by coronal mass ejections (CME), occurred.

As long as the Earth is withing the ejection propagation sector, space weather specialists forecast a magnetic storm of the highest class. However, disturbance intensification rate and its average level surpassed all expectations. Due to the overlapping effect from six CMEs, the storm had the planetary index of geomagnetic disturbance Kp=8 one hour after its beginning and it remained above this level for 30 hours.

The highest index Kp=9 was observed for 9 hours. According to the Digital Observations Bank at Paratunka Geophysical observatory, the local index of geomagnetic disturbance reached K=8 on 15 May 2005 (only for three hours), and K=9 has never been observed. The highest index of geomagnetic disturbance Kp=9 was previously recorded druing the Halloween storm on 29-30 October 2003. In total 22 such storms have been recorded since 1932.

Aurora was observed over the whole territory of the Russian Federation up to the Caucasгs. Unfortunately, it was cloudy over the Kamchatka Peninsular and there were no reports on aurora. It was not recorded by the all-sky camera installed at IKIR FEB RAS according to the international Agreement with the Japanese Institute.

Aurora was also observed over the whole Europe up to Italy, France, Spain, in New Zeeland, in all the USA states and in Mexico. It was seen by the people of Porto Rico for the first time after 1859 and 1921.

Aurora space weather forecast system, developed by the institute staff, recorded the CME effect on cosmic ray intensity almost from the moment of ejection. As the CME approached the Earth, the maximum moved to higher frequency region.