Space Weather
Geomagnetic Storms
Geomagnetic storms — disturbances of Earth's magnetic field driven by the Sun — and the NOAA G1–G5 scale, plus the Kp index behind aurora forecasts. Current storm status is prepared for NOAA SWPC; none is fabricated.
Night SkyReference data
What a geomagnetic storm is
A geomagnetic storm is a temporary disturbance of Earth's magnetosphere caused by the solar wind — especially by coronal mass ejections. Storms drive the aurora to lower latitudes and, when strong, can affect power grids, satellites, and navigation.
The G1–G5 storm scale
- G1
- Minor: weak power-grid fluctuations; aurora at high latitudes.
- G2
- Moderate: aurora reaches mid-high latitudes.
- G3
- Strong: aurora at mid-latitudes; possible satellite and navigation effects.
- G4
- Severe: widespread aurora and grid/navigation impacts.
- G5
- Extreme: aurora far from the poles; major infrastructure risk.
Sources & references
The primary and reference sources this topic draws on.
- NOAA SWPCNOAA Space Weather Prediction Center
Space-weather forecasts and alerts: aurora (OVATION), the Kp index, and the G1–G5 geomagnetic storm scale.