A severe geomagnetic storm is hitting the Earth these days. What are the causes of this phenomenon?

A severe geomagnetic storm is underway after solar flares sent plasma toward Earth, and the Aurora Borealis will be visible in areas across the southern United States starting today.

Aurora Borealis, visible in case of geomagnetic storms PHOTO Adevărul archive

The US National Oceanic and Atmospheric Administration's (NOAA) Space Weather Prediction Center (SWPC) issued a Geomagnetic Storm Alert on Sunday after sun-observing satellites recorded an X-type 1.1 solar flare and later a corona hole high speed corona (CH HSS), reports Fox Weather.

Auroras occur when charged particles from the Sun interact with Earth's atmosphere, creating what are known as the Northern and Southern Lights.

On the five-point scale of geomagnetic storms, space experts believed the first wave of energy could be ranked as either a G1 or G2, but could rise to a G3 on Monday.

However, severe G4 space weather conditions have been observed in the past 24 hours and are expected to continue, according to the SWPC dashboard.

A G1 class geomagnetic storm is the weakest and typically results in auroras near the Arctic Circle.

A G3 storm allows an aurora to be seen as far away as Washington, Wisconsin and New York if the sky is clear. Level 4 of 5, leading to Northern Lights could be visible as far away as Alabama and Northern California.

The amount of geomagnetic activity is also monitored by ground-based magnetometers, and the event is measured on the Kp index scale, which ranges from 0 to 9.

The University of Alaska Fairbanks Institute of Geophysics is forecasting high aurora activity with Kp-6 levels through Monday evening.

Space experts say that accurately determining the strength of geomagnetic activity is difficult, even with more frequent occurrences.

Geomagnetic storms have become more numerous in the past year as the Sun begins to reach the maximum phase of the solar cycle.

A solar cycle is a sequence that the Sun's magnetic field goes through every 11 years, when the field reverses. Solar cycle 25 started in 2019 and could last until 2030.