Earth is preparing for an increase in solar activity, with a significant coronal hole expected to trigger geomagnetic storms of G2 and G3 intensity between September 13-14, 2025. These disturbances could persist for up to six days, with the peak activity anticipated from September 14-16. This period of heightened solar wind follows an unusually active September for geomagnetic events, with three major storms recorded in the first ten days of the month, a notable increase compared to August's single event.
Coronal holes are areas on the Sun's surface where magnetic fields weaken and open, allowing high-speed streams of charged particles, known as solar wind, to be released. This solar wind is typically faster and denser than the standard solar wind, leading to disruptions when it interacts with Earth's magnetosphere. The coronal hole in question reached the Sun's visible disk center on September 11, 2025, initiating the expected geomagnetic disturbances. While initial assessments suggested storms might not exceed G2 levels, these were preliminary, as precise measurements can only be taken once Earth is within the affected space region.
Adding to the unusual activity, an unexplained magnetic storm impacted Earth on September 10, 2025, with no clear solar event identified as its cause. This event occurred as the Sun's overall activity has seen a significant increase of approximately 70% over the last three months, returning to levels observed in early 2024. Solar Cycle 25 has been notably more active than initially predicted, with solar activity increasing significantly since its start in December 2019. The peak of Solar Cycle 25 is expected around mid-2025.
Geomagnetic storms, while capable of producing beautiful auroral displays at high latitudes, can also lead to minor disruptions. These can include impacts on satellite and GPS systems, as well as minor fluctuations in power grids. Experts advise vigilance in protecting sensitive electronic devices and monitoring communication systems during these periods. The solar wind speed from coronal holes can range from 500 to 800 kilometers per second, significantly faster than the slow solar wind typically found in equatorial regions. The interaction between these fast and slow streams can create corotating interaction regions (CIRs), which can also contribute to geomagnetic disturbances.