Since last week the sun has been spewing out a steady stream of solar flares causing the NOAA Space Weather Prediction Center to issue a geomagnetic storm warning.

On Sept. 6 NASA’s Solar Dynamics Observatory observed two flares, the first recorded at X2.2 and a second at X9.3, the largest flare in more than a decade.

X-class flares are the most intense and the last flare of this magnitude was a X9.0 recorded back in Dec. 2006.

“This flare is the capstone on a series of flares, which was identified on Aug. 29 and is currently rotating off the front of the sun as part of our star’s normal rotation,” NASA SDO stated in a blog post. NASA SDO also noted that this level of activity was rare at this stage of the 11-year solar cycle.

“This is a phase when such eruptions on the sun are increasingly rare, but history has shown that they can nonetheless be intense,” they said.

A series of smaller flares from same region, dubbed Active Region 2673, preceded the Sept. 6 flare and a X8.2 flare was also observed on Sept. 10.

Big solar flares, like the one on Sept. 6, create coronal mass ejections, a giant cloud of solar plasma embedded with magnetic field lines.

These cause major disturbances in the Earth’s magnetosphere, the area of space surrounding Earth, which can create geomagnetic storms.

NOAA issued a moderate geomagnetic storm watch for Sept. 13 and a minor geomagnetic storm watch for Sept. 14.

Geomagnetic storms can impact satellites, navigation and communications systems and they also mean that Northern Lights will be enhanced.