The particles from the coronal mass ejection (CME) can also cause aurora activity as they interact with Earth's magnetosphere, so keep your eyes on the skies. They should be arriving within a few days.
Actually, it spat out two X-class flares, on the morning of 6 September EDT. These are the biggest class of solar flare there is, and the largest explosions in our solar system, with loops of plasma tens of times the size of the Earth.
The first one came in at X2.2 at 5.10am EDT. Then, just a few hours later at 8.03am, it dropped a monster X9.3 flare, the largest since 2005. Both flares erupted from an active region called AR 2673, which also produced an M-class flare a few days ago. Of the two sunspot regions currently active, both flares came from the smaller - a size of just 7 Earths by 9 Earths.
Meanwhile the flare produced by the M5.5 ejection on September 4, 2017 arrived at the DSCOVR spacecraft on September 6 at 23:08 UTC and at Earth 30 minutes later. The impact did not spark a geomagnetic storm, but the potential still exists as the CME continues passing over Earth.
This solar cycle, the Sun's 11-year periodic activity cycle, began in 2008. It has been unusually quiet, with very low sunspot activity. But although we're moving into solar minimum, the quietest period of the cycle, activity can – and obviously still does - occur.
How long sunspots last varies. The longest-lived sunspot on record hung around for six months, so it's entirely possible we haven't heard the last from AR 2673.
Credit for top image: https://nexusnewsfeed.com/article/science-futures/the-sun-just-erupted-the-biggest-solar-flare-in-12-years-and-it-has-affected-earth/