A high-intensity solar flare causes a severe geomagnetic storm and a rare particle event On 11 November, at 10:04 Canary Islands time, the Sun emitted a powerful X5-class solar flare, one of the most intense recorded in this solar cycle. The phenomenon originated in active region 4274 and was accompanied by at least two coronal mass ejections (CMEs) that were launched directly towards Earth. These ejections travelled at high speed and their impact occurred earlier than expected, triggering a severe geomagnetic storm, classified as level G4 on the scale that classifies the intensity of this