On Palm Sunday, Finland experienced the strongest geomagnetic storm of the year so far. The storm was caused by a coronal mass ejection from the Sun, which was detected in images taken by satellites. Despite being predicted to hit the Earth about a day in advance, the intensity of the geomagnetic disturbances caused by it was surprisingly strong.
The eruption led to strong changes in the electron density of the ionosphere, affecting the flow of radio signals. Previous geomagnetic storms of a similar level occurred last year, with 2017 seeing the most intense space weather turbulence. Tiera Laitinen, head of the Space Weather Research group at Finnish Meteorological Institute explained that this variation is due to the Sun’s activity fluctuation, with more storms expected in the coming years as we approach the maximum activity period.
Geomagnetic storms are measured using various indices such as Kp index, which reached a value of 8+ during this particular storm and was classified as severe. While these types of space events can be measured in several ways, Kp index is considered one of the most important measures for tracking them.