Geomagnetically Induced Currents (GIC)
When Earth's magnetic field changes rapidly during a geomagnetic storm, it induces electric fields in the ground. Long conductors such as power lines and pipelines can then carry geomagnetically induced currents (GIC). These are DC-like currents that can saturate transformers, cause heating, and in extreme cases damage equipment. High latitudes and long transmission lines are most at risk.
Historical Events
March 1989: A severe storm caused blackouts in Quebec when GIC damaged transformers. Carrington Event 1859: Telegraph systems were affected. Today, grid operators use space weather forecasts to prepare (e.g. reduce load, avoid critical operations) when strong storms are expected. Cosmic Radar shows the daily Kp so you can see when storm conditions may affect infrastructure.
Sources and further reading
- NOAA – Power grid impacts – GIC and grid operations
- ESA – Space weather effects – Infrastructure
- NASA – Geomagnetic storms – Science and monitoring