When the solar wind or a CME disturbs Earth's magnetic field, we call it a geomagnetic storm. NOAA's G-scale (G1–G5) ranks the severity — and each step up brings significantly more impact to technology and infrastructure.
When the solar wind or a CME disturbs Earth's magnetic field, we call it a geomagnetic storm. NOAA's G-scale (G1–G5) ranks the severity — and each step up brings significantly more impact to technology and infrastructure.
A geomagnetic storm occurs when sustained energy transfer from the solar wind disturbs Earth's magnetosphere. The key inputs are solar wind speed, density, and — most critically — a sustained southward IMF (negative Bz).
Geomagnetic storms aren't just an aurora trigger — they cause measurable problems across multiple technology sectors.
The G-scale gives operators a shared language to prepare. Most space weather is routine — but the tail risk from extreme events is why governments and grid operators take it seriously.