Earth has been hit by a solar storm that’s set to be the strongest in 21 years and could disrupt power lines and communications.

Satellites recorded the storm as G5 (geomagnetic 5) strength around 8 p.m. Friday, the most strongest level available. It’s the first G5-level storm since October 2003.

A NOAA Space Weather Prediction Center tweet said: ‘Extreme (G5) geomagnetic conditions have been observed!’

The solar storms are set to last all weekend and potentially threaten power grids. They could cause widespread electrical disruptions, blackouts, and damage to critical infrastructure.

The solar flares’ results are visible in the form of stunning auroras, which are currently being seen worldwide.

The storm is caused by six streams of plasma that have burst from the sun and are hurtling toward Earth.

Now that the streams of plasma are roughly one million miles from the planet, scientists can gauge the severity of the storm.

The NOAA Space Weather Prediction Center released an update stating that the geomagnetic storm would be a 6 on the K-index, a scale that quantifies disturbances in the Earth’s magnetic field. The scale ranges from 0, which is calm, to 9, which is severe.

A 6 is considered a moderate geomagnetic storm, meaning that power systems at high latitudes are especially vulnerable and can experience emergency situations.

If this particular geomagnetic storm should prove long, transformers and other electrical equipment could suffer damage.

The NOAA’s current forecast is higher than their previous prediction, which was a 5.

Dr. Tamitha Skov, a NOAA space weather physicist, announced that the geomagnetic storm was a G5 on the Hp30 index. This index is a scale like the K-index, but it measures disturbances in shorter windows (30 minutes versus three hours).

A G5 storm would represent an extreme geomagnetic storm, a possibility that would be replete with serious problems and inconveniences.

At the farthest end of the index, a G5 would entail serious transformer damage and widespread blackouts.

High-frequency radio communications could possibly be rendered incapacitated for a few days.

And satellite navigation services, such as GPS, could be off-line for several days.

Dr. Skov wrote that time would ‘tell if this #solarstorm has the punch to cause the (K-index) to reach G5 as well.’

Scientists have also predicted that three of the six streams, known as coronal mass ejections (CMEs), could combine to create a powerful ‘cannibal CME.’