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.

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Sources & references

Facts on this topic will be cited from these primary and reference sources.

NOAA SWPCNOAA Space Weather Prediction Center
Space-weather forecasts and alerts: aurora (OVATION), the Kp index, and the G1–G5 geomagnetic storm scale.

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