Comment added at 11:15 UTC on October 28: Region 10486 was the source of a major M8.4 long duration event peaking at 10:48 UTC. This event occurred in the eastern part of the region and may have triggered a superflare in the remainder of the region, this flare peaked at 11:10 UTC. This superflare has so far peaked at the class X18 level which makes it the second largest flare during cycle 23. The event is likely to be associated with an enormous earth directed CME. The CME will likely reach the Earth sometime between 8 and 17 UTC on October 29. This will be a direct hit and extremely severe geomagnetic storming is possible.