Halloween Solar Storms (2003)
October-November 2003What Happened
A series of powerful solar storms produced the largest flare ever recorded by GOES satellites—estimated at X45. Three massive sunspot groups, the largest 13 times Earth's size, launched CMEs at 2,125 km/s. The resulting G5 storm affected over half of Earth's orbiting satellites and destroyed a Japanese scientific satellite.
Outcome
Sweden experienced a one-hour power outage. Airlines rerouted polar flights. Satellite operators switched to backup systems. Auroras appeared as far south as Texas and the Mediterranean.
Space agencies upgraded monitoring systems and warning protocols. The event became the benchmark for severe space weather until May 2024.
Why It's Relevant Today
The January 2026 radiation storm exceeded the Halloween Storms' intensity on NOAA's S-scale, marking the first time in 23 years that record was surpassed. However, infrastructure weathered the 2026 event better, suggesting improved preparedness.
