The plasma clouds that had been traveling toward Earth since the beginning of October reached the planet on 10 October. At around 14:34 UTC, a clear coronal mass ejection signature appeared in the solar wind, and at 15:16 UTC magnetometers recorded a sudden impulse. NOAA successively raised its warning levels: first an index of Kp=5 (G1) was expected, then Kp=6 (G2), and by 17:42 UTC — Kp=7 and higher (G3, a strong storm).
The impact proved noticeably more powerful and faster than most preliminary estimates. The geomagnetic field reached G3 level already at around 17:58 UTC, and according to the high-resolution Hp30 index, values corresponding to even G4 were briefly recorded. The solar wind speed quickly rose from about 380 to nearly 890 km/s, the magnetic field intensified, and the southward component Bz plunged deep into negative territory. For the high latitudes of Europe, this created good conditions for auroras.
On the same day, 10 October, active region AR4549 produced another M6.4–M6.5 flare. It occurred almost simultaneously with the arrival of the previous cloud. The new ejection also headed toward Earth, though not strictly along the central line.
By 11 October, the main phase of the strong storm had ended. Conditions gradually eased, but one more impact remained en route — from the previous day's flare. It was expected to arrive within the next one to two days.
On 12 October, the Sun continued its activity. Two large plasma filaments detached and headed roughly toward Earth. A direct hit is unlikely, but a glancing blow is possible in 2–3 days. At the same time, Earth is under the influence of a high-speed solar wind from large coronal holes. This combination maintains an elevated probability of new geomagnetic disturbances and auroras at mid-latitudes in the coming week.
The series of events that began with the growth of sunspots at the center of the disk on 5–6 October passed through moderate and then strong storms. The G3 level became the most notable episode of the current autumn. Activity is now gradually shifting toward the western edge of the solar disk, but fresh filament eruptions and streams from coronal holes show that a quiet period has not yet arrived. Observations continue, and the exact effects of the new eruptions will become clear after analysis of coronagraph data.
