NASA's Solar Dynamics Observatory, which watches the sun constantly, captured images of the events. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel.
This video shows the sequence of M and X flares starting on Sept. 4, 2017, and culminating with an X9.3 flare -- the largest of the solar cycle so far, on Sept. 6.
Download from: https://svs.gsfc.nasa.gov/12706