What is a Geomagnetic Storm?

Geomagnetic Storm: A geomagnetic storm is a major disturbance in the Earth’s magnetosphere. When unusually strong solar wind waves (charged particles from the Sun) pass over the Earth, the effect causes changes in the magnetic field surrounding the planet. Geomagnetic storms can cause disruptions in high-frequency radio communications across the polar regions, GPS positioning errors, and are also responsible for the northern and southern lights. In extreme cases, they can damage electrical power transmission lines and anything related to voltage control, and can cause power outages. The NOAA/SWPC classifies geomagnetic storms as G1 (minor), G2 (Moderate), G3 (Strong), G4 (Severe), and G5 (Extreme)  — Cengiz Avci