This flare is classified as an X3.1-class flare.
X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc.
The flare erupted from a particularly large active region -- labeled AR 12192 -- on the sun that is the largest in 24 years. This is the fourth substantial flare from this active region since Oct. 19.
The giant active region on the sun erupted on Oct. 26, 2014, with it's sixth substantial flare since Oct.19. This flare was classified as an X2-class flare and it peaked at 6:56 am EDT.
Continuing a week's worth of substantial flares beginning on Oct.19, 2014, the sun emitted two mid-level solar flares on Oct. 26 and Oct. 27. The first peaked at 8:34 pm EDT on Oct. 26, 2014, and the second peaked almost 10 hours later at 6:09 am EDT on Oct. 27. NASA's Solar Dynamics Observatory, which constantly observes the sun, captured images of both flares.
A large active region on the sun erupted with another X-class flare, an X2.0, on Oct. 27, 2014 -- its fourth since Oct. 24. The flare peaked at 10:47 a.m. EDT.
The sun emitted a mid-level solar flare, an M6.6-class, peaking at 11:32 pm EDT on Oct. 28, 2014