The show of Northern Lights it returned to illuminate the Italian skies on the night of November 12, 2025 with numerous sightings between 4 and 5 am especially along the Alpine arcfrom Piedmont to Trentino-Alto Adige. Webcams and enthusiasts have captured spectacular images of auroral phenomena with the characteristic reddish and purple colors typical of the latitudes of Northern Italy. Auroral phenomena have been spotted in many other parts of the world, for example in Canada and the USA also in southern states such as Texas, Florida and Arizona.
What caused this suggestive atmospheric phenomenon – which consists in the interaction of charged particles coming from the Sun and the atoms of the Earth’s atmosphere – was a “severe” category G4 geomagnetic storm (in the official scale which reaches up to G5). The intense disturbance of the Earth’s magnetic field followed the arrival of a violent one coronal mass ejectiona rapid, dense stream of high-energy charged particles from the Sun emitted by a X5.1 class flareone of the most intense recorded in this solar cycle, originating yesterday morning around 11 from the active region AR 4274.
The geomagnetic storm is not over yet: the effect of yesterday’s coronal ejection added to that of the ejections of recent days and at the moment, after a partial decrease in the last few hours, we are once again in conditions of a rather intense geomagnetic storm. The intensity of this event was important – there was even a flow of solar protons to the ground – due precisely to the overall effect of all the coronal ejections that reached our atmosphere.
According to the forecasts of Space Weather Prediction Center of NOAA, the situation is not destined to improve in the next few hours: a new intensification of geomagnetic disturbance with the possibility of a return to the G4 category today, while the achievement of the target is currently expected for tomorrow category G3. These are geomagnetic storms that can lead to anomalies and malfunctions of GPS systems, interruption of high frequency radio communications, navigation problems for artificial satellites and, indeed, polar auroras visible even at latitudes of 45°, those of Northern Italy.
THE’Kp indexwhich measures the extent of geomagnetic disturbance, reached a value of 8.67which is particularly high. To be clear, a Kp of 7 is sufficient to spot auroral phenomena in Northern Italy. This explains the abundance of sightings that occurred at night in the Alpine regions.
