G4-Class Geomagnetic Storm: Assessing Risks to India’s Critical Infrastructure

The National Oceanic and Atmospheric Administration (NOAA) recently issued a G4 (Severe) Geomagnetic Storm Watch, marking the first such alert since 2005. This escalation in space weather is attributed to a series of massive solar flares and Coronal Mass Ejections (CMEs) originating from a large, complex sunspot cluster. As Solar Cycle 25 approaches its predicted maximum, such events highlight the vulnerability of modern technological civilizations to extraterrestrial physical phenomena. A geomagnetic storm occurs when CMEs—vast clouds of plasma and magnetic fields from the Sun—interact with Earth’s magnetosphere. This interaction causes major disturbances in the magnetic environment. The G-scale, ranging from G1 (Minor) to G5 (Extreme), quantifies these impacts. A G4 event can induce significant electrical currents in the ground, potentially damaging high-voltage power transformers and causing widespread grid instabilities.