A magnetic storm has begun on Earth quite unexpectedly
About an hour ago, global networks of magnetic observatories detected a planetary-scale geomagnetic storm. The event began between 4:00 and 5:00 a.m. UTC. As of this writing — around 6:00 a.m. — the storm is at the G1 level, meaning it is classified as minor.
A deterioration in geomagnetic conditions had been anticipated the day before, though it was expected that space weather changes would remain within the range of minor disturbances. Frankly, until now, it appeared that this would indeed be the case. Solar wind parameters near the planet had remained low throughout this period, making it unclear exactly how they managed to drive Earth's magnetic field into a storm state; nevertheless, the situation is what it is.
August is shaping up to be a rather active month so far: this is the third magnetic storm in just 18 days (previous ones occurred on the 2nd and 8th), a fact that contrasts sharply with the generally low level of solar activity. However, all the storms observed to date have been moderate, with none exceeding the G2 threshold on the five-point scale (where G5 is the highest level).
The current event is expected to be short-lived. Forecasts indicate that Earth's magnetic field will return to a state of minor disturbance by noon Moscow time. At the same time, full stabilization of conditions may take two to three days. Earth is currently within the influence zone of a rather large coronal hole, and until this influence subsides, further spikes in geomagnetic disturbance remain possible.