What it is
The sun periodically throws off bursts of charged particles called coronal mass ejections. When one strikes the Earth's magnetic field it can drive currents through long power lines and pipelines. NOAA rates these geomagnetic storms from G1 (minor) to G5 (extreme). At G5, NOAA warns of widespread voltage control problems, some grid systems possibly collapsing and transformers that may be damaged.
An electromagnetic pulse, or EMP, is a man-made cousin: a nuclear detonation high in the atmosphere can produce a pulse that damages unprotected electronics across a wide area.
What history shows
On September 1, 1859, the Carrington Event drove currents through telegraph wires strong enough to shock operators and start fires. It remains the largest geomagnetic storm on record, and it struck a world with almost no electrical infrastructure.
In May 2024, at least eight eruptions reached Earth over four days. NOAA observed G5 conditions on May 10 and later described the storm as possibly the strongest of this century, with auroras seen far to the south. The grid held, but operators were on alert.
In 1962, a U.S. high-altitude nuclear test over the Pacific, Starfish Prime, disrupted streetlights and telephone service in Hawaii, hundreds of miles away.
What it does to a household
The danger is not the storm itself, which is invisible on the ground. It is what follows if large transformers are damaged. These are custom-built, heavy and slow to replace, so the worst cases imagine outages measured in weeks or months across a region, with water treatment, fuel distribution and communications failing alongside.
How we design for it
We plan as if the grid may be down for a long time. Beyond solar, storage and backup generation, estates get surge protection at the service entrance and on critical circuits, and spare critical electronics, inverter controls, charge controllers and radios, stored in shielded enclosures. Essential systems keep non-electronic backups: mechanical well pumps, wood heat, manual valves and paper procedures.
What you can do now
Ask what in your home would still work if every electronic device failed at once. The answer is usually very little, which is why we design mechanical fallbacks into every system.
This page is general information to help you plan. It is not engineering, medical or legal advice. Every Styrkholm project is designed by licensed professionals for the specific site and household.