Geomagnetic Storm

A geomagnetic storm occurs when a surge of solar wind energy — typically from a coronal mass ejection (CME) — significantly compresses and disturbs Earth's magnetosphere. NOAA rates storms from G1 (minor) to G5 (extreme). Effects include expanded thermosphere increasing drag on LEO satellites (the February 2022 G2 storm destroyed 40 newly deployed Starlink satellites), surface charging on spacecraft, GPS signal degradation, HF radio blackouts, induced currents in power grids (the 1989 Quebec blackout was caused by a G5 storm), and aurora visibility at unusually low latitudes.