ALERT: Geomagnetic K-index of 4 Alert issued on November 5

A Geomagnetic K-index of 4 Alert was issued on November 5, 2025. The alert indicates that the geomagnetic activity threshold was reached at 19:36 UTC, and it is valid for the synoptic period from 18:00 UTC to 21:00 UTC. The alert remains active as of the issued time, 19:40 UTC.

Potential impacts from this event are expected primarily poleward of 65 degrees geomagnetic latitude. Weak power grid fluctuations may occur due to induced currents. Additionally, aurora may be visible at high latitudes, including regions such as Canada and Alaska.

The alert is being issued during a period of generally active geomagnetic conditions, influenced by a prolonged southward interplanetary magnetic field (Bz). Solar wind parameters are near nominal but a series of powerful flares, including an X1.8 flare at 04/1734 UTC (from Region 4274) and an M7.4 flare at 05/1119 UTC, have recently occurred. While the majority of associated coronal mass ejections are expected to pass behind Earth, ongoing complex solar activity is being monitored closely due to the potential for further geomagnetic disturbances.