"Seventeen major flares erupted on the Sun between 19 October and 5 November 2003, including perhaps the most intense flare ever measured on the GOES XRS sensor – a huge X28 flare,[17] resulting in an extreme radio blackout, on 4 November. These flares were associated with CME events which impacted the Earth. The CMEs caused three geomagnetic storms between Oct 29 and November 2 during which the second and third storms were initiated before the previous storm period had fully recovered. The minimum Dst values were -151, -353 and -383 nT. Another storm in this event period occurred on November 4 – 5 with a minimum Dst of -69.nT. The last geomagnetic storm was weaker than the preceding storms because the active region on the Sun had rotated beyond the meridian where the central portion CME created during the flare event passed to the side of the Earth. The whole sequence of events is known as the ‘Halloween Storm’.[18] The Wide Area Augmentation System (WAAS) operated by the Federal Aviation Administration (FAA) was offline for approximately 30 hours due to the storm.[19] The Japanese ADEOS-2 satellite was severely damaged and the operation of many other satellites were interrupted due to the storm.[20]"
