A rare G4 geomagnetic storm has made (and will still make?) the Northern Lights visible in Europe and Italy: risks for technologies, advice for observing and photographing them.
In the last few hours, the Earth has been hit by a severe geomagnetic storm, classified as G4 level by NOAA, the US space weather service. This is a rare event: only very few warnings of this level have been issued throughout the current solar cycle.
The origin is a series of coronal mass ejections (CMEs), large clouds of plasma and magnetic fields hurled from the Sun into space. One of these clouds reached our planet in the early hours of November 12, triggering a strong response from the Earth’s magnetic field. According to the bulletin, storm conditions reached the G4 level at 01:20 UTC, i.e. 2:20 in Italy and central Europe.
What is the result of all this?
The most spectacular effect of all this, at least for ordinary people, are the auroras: the spectacular colored lights that fill social media at the moment, also captured at unusual latitudes (as in the case of the opening photo, taken in England, or the one published below, even captured by a webcam in Abruzzo). The Northern Lights arise from the interaction between the charged particles emitted by the Sun and the gases of the Earth’s atmosphere (especially oxygen and nitrogen). Since the Sun’s activity is not constant but follows a cycle of approximately 11 years, and we are close to the solar maximum, this causes the flow of particles to be particularly intense: it is precisely this condition that favors the phenomena observed in these hours.
The Kp index – a scale from 0 to 9 that measures how “agitated” the magnetic field is – shows values up to 8–8.5 in the early morning hours (red, corresponding to G4) and later around 7 (orange, G3 level). In practice, between 3 and 10 am in Europe the storm was particularly intense, with a slow decline towards late morning.
The phenomenon is still ongoing
Updates from the prediction center indicate that the “heart” of the magnetic cloud is still passing over the Earth and that new oscillations between G1 and G4 levels are possible in the next few hours. Furthermore, an even more energetic CME could arrive in the late European afternoon-evening of today November 12 (around 7:00 pm Italian time, estimate based on NOAA models), extending the event into Thursday night.
What does all this mean for Europe? In our latitudes the direct effects on the population are limited. The main risks concern the most sensitive technological infrastructures: high voltage electricity grids, satellites, GPS navigation systems and long-distance radio communications.
Network operators and satellite operators have been alerted and can implement mitigation strategies, for example by modifying power flows or changing satellite operating modes.
Where the effects will occur
For the public the most spectacular effect is the possibility of seeing the Northern Lights. With a Kp close to 8 the auroral oval expands significantly towards the south: on the night between 12 and 13 November the auroras could be visible not only in Scandinavia and Scotland, but, if the storm remains at high values, also in Ireland, northern Germany, Poland and the Baltic countries. Further south, in Italy, there could be some demonstrations on the horizon, especially in the Alpine regions.
In summary, we are experiencing one of the most intense space weather episodes of this solar cycle. There’s no reason to be alarmed, but it’s a great time to follow official updates closely and, for those far enough north and under clear skies, to look up, try to observe a rare sight and perhaps capture it with your smartphone. By the way: don’t expect to see with the naked eye the effects you admire in the photographs, because even the most natural shots, that is, even those not retouched with apps or software, benefit in any case from a longer exposure time than that of the human eye and therefore the effects are all a little amplified.
