But the mechanisms that drive these solar flares are still unknown, making attempts to forecast them troublesome.
When a solar flare and associated CME erupted in Earth’s direction on March 31, 1989, power down went across Quebec, Canada, as well as parts of northeastern US.
An estimated six million people were cut off from electricity for up to nine hours.
And 130 years earlier, on August 28, 1859, the largest known solar storm caused telegraph systems across Europe and North America to fail.
source: express.co.uk