The Halloween solar storms were a series of solar storms involving solar flares and coronal mass ejections that occurred from mid-October to early November 2003, peaking around October 28–29.[1][2][3] This series of storms generated the largest solar flare ever recorded by the GOES system, modeled as strong as X45 (initially estimated at X28 due to saturation of GOES' detectors).[4][5]
Effects
On Earth
Satellite-based systems and communications were affected, aircraft were advised to avoid high altitudes near the polar regions,[6] and a one-hour-long power outage occurred in Sweden as a result of the solar activity.[2]Aurorae were observed at latitudes as far south as Texas[2] and the Mediterranean countries of Europe.[6] Twelve transformers in South Africa were disabled and had to be replaced, despite the country's low geomagnetic latitude.[7]
On satellites and spacecraft
The SOHO satellite failed temporarily and the Advanced Composition Explorer (ACE) was damaged by the solar activity.[2] Numerous other spacecraft were damaged or experienced downtime due to various issues. Some of them were intentionally put into safe mode in order to protect sensitive equipment.[6] Astronauts aboard the International Space Station (ISS) had to stay inside the more shielded parts of the Russian Orbital Segment to protect themselves against the increased radiation levels.[8]
One of the solar storms was compared by some scientists in its intensity to the Carrington Event of 1859.[9]
These events occurred during solar cycle 23, approximately three years after its peak in 2000, which was marked by another occurrence of solar activity known as the Bastille Day event.