An active sunspot region on the Sun erupted in the most powerful class of flare of which our Sun is capable on 31 March at 17:27 UT.
It is the most powerful of the flares. At the time of writing, there were 36 flares, of which one was a small B-class flare, 29 were C-class flares, and 9 were more powerful M-class flares.
Each class of flares is ten times more powerful than the previous class. The X28 flare that hit Earth in November 2003 was the most powerful flare on record.
There can be shenanigans when solar flares are unleashed in the general direction of Earth. When solar particles collide with the Earth's magnetic field and atmosphere, there are storms.
The X-class flare came from the same location.
These will mostly go unrecognized by the surface-dwellers. They can cause some radio and navigation blackouts, maybe some power grid fluctuations, and spectacular Aurorae lighting up the polar skies as particles, accelerated along Earth's magnetic field lines, are deposited at the poles, where they interact with the atmosphere.
A strong geomagnetic storm should have been caused by a massive CME associated with two of the M-class flares. Unless you were taking pictures of the Auroras, you probably didn't notice anything.
The X-class flare and the powerful M9 flare that followed did happen on the Earth-facing side of the Sun, but that is not a guarantee of geomagnetic storms. The region is currently rotating away from Earth, and any solar particles launched into space may deliver just a glancing blow.
According to Spaceweather, the X1 flare is unlikely to have any significant Earth impacts, but the chance of the Aurora is high over the first few days of April.
The X-ray emission is associated with a flare. The NASA SDO.
If you think you've been hearing a lot about the Sun lately, you're right. Since mid-January, our star has had eruptions every day, and a lot of activity prior to that. This is normal. Every 11 years, the Sun goes through activity cycles with a clearly defined minimum and maximum.
When the solar magnetic field is weak, the minimum takes place. The solar poles switch places when the magnetic field flips. The sunspot and flare activity increases as the magnetic field grows stronger.
The most recent solar minimum took place in December. Similar levels of activity are shown in previous solar cycles.
We have unprecedented eyes on the Sun, as the solar maximum is due to take place in July. The European Space Agency and NASA are very close to our star and are getting very personal with it. We are expecting to learn a lot about why the Sun behaves the way it does.