Strongest Radiation Storm in 20 Years Batters Earth — Where Will The Northern Lights Be Visible?

Earth is under siege from one of the most intense solar storms in decades. A colossal eruption on the Sun has hurled a wave of charged particles directly towards our planet. The storm has already caused geomagnetic disturbances strong enough to disrupt power grids and is lighting up the skies with dazzling auroras visible further south than usual.

This rare event is not only a spectacle for sky‑watchers but also a serious test for modern infrastructure. Power grids, satellites, and communication systems are all vulnerable to the storm's intensity, reminding us how dependent we are on technology that can be disrupted by forces far beyond our control.

Why the Solar Storm Is So Powerful

The current space weather event is the result of a giant X1.9-class solar flare, the most powerful type of flare the Sun can emit. While solar flares alone do not trigger geomagnetic storms, this flare was accompanied by a coronal mass ejection, or CME. Think of it as a massive solar sneeze: billions of tons of plasma and magnetic fields were hurled into space, directly toward Earth.

When the CME slammed into Earth's magnetosphere, it accelerated charged particles already trapped in the planet's magnetic field. As these particles plunged into the upper atmosphere, they collided with atmospheric gases, producing the colourful light displays known as auroras. The storm is currently classified as G4, a severe geomagnetic storm, with experts warning it could briefly reach G5 levels — the category responsible for extraordinary aurora displays in May 2024.

What an S4 Radiation Storm Means

Alongside the geomagnetic disturbances, the Sun has unleashed a solar radiation storm, the strongest in over 20 years. The Space Weather Prediction Center announced the event as an S4 storm, the second-highest intensity level, which accelerates highly energetic protons toward Earth.

Radiation storms of this scale can disrupt radio communications, interfere with spacecraft operations, and affect satellites. X-ray radiation from the initial flare has already caused temporary radio blackouts in some regions. For perspective, the last S4 radiation storm occurred in October 2003, part of the Great Halloween Solar Storms that lit up skies as far south as Florida and California.

Where the Northern Lights Can Be Seen

Thanks to the storm, the northern lights were visible much farther south than usual. On 19 January, auroras lit up skies across large swathes of the northern United States, including Oregon, Illinois, Pennsylvania, New York and Alaska. The geomagnetic activity was strong enough to push visibility as far south as Alabama and California.

When viewing the northern lights, experts recommend looking toward the northern horizon, away from city lights, to catch the vivid green, red, and purple auroras dancing across the sky.

How Solar Activity Creates These Stunning Lights

Auroras occur when charged particles from solar eruptions interact with gases in Earth's upper atmosphere. The collisions excite the gases, producing glowing lights that shimmer in green, red, and purple hues. Geomagnetic storms, like the current G4 event, are caused by CMEs, while radiation storms result from faster-moving charged particles released by the flare.

This dual impact of charged particle streams and magnetic disturbances makes the current solar storm exceptionally dramatic. Beyond the visual spectacle, scientists continue to monitor its effects on power grids, satellites, and communication systems to mitigate potential damage.