A coronal mass ejection (CME) is a burst of magnetised solar plasma. When it reaches Earth, it slams into and compresses the magnetosphere — the planet's protective magnetic bubble. The rapidly changing magnetic field then induces slow geomagnetically induced currents (GICs) in long conductors on the ground, most importantly high-voltage power transmission lines, which can overheat transformers and, in severe cases, trip out parts of the grid.
The 1989 Quebec blackout, triggered by a geomagnetic storm, knocked out power to six million people in about 90 seconds after a transformer failure at the Hydro-Québec grid — a reminder that space weather is a genuine infrastructure risk, not just an aurora show.
A coronal mass ejection races from the Sun toward Earth, compresses the magnetosphere on impact, and drives geomagnetically induced currents through a schematic power grid — showing why grid protection and home preparedness both matter.
Storm intensity (Kp) sets how hard the magnetosphere compresses and how strong the induced currents in transmission lines become; protective relays cut GIC flow into transformers, and a stocked home kit softens the impact of any resulting outage.
Set the Kp storm intensity and CME speed, toggle grid relays and home kit readiness, then press "Launch CME" and watch the transit time, GIC level, transformer risk, and home outage impact update as the ejecta arrives.
The March 1989 geomagnetic storm collapsed Hydro-Québec's entire grid in about 90 seconds, leaving six million people without power — a single failed transformer can cascade in minutes.