Sun releases the largest solar radiation storm ‘in over 20 years,’ forecasters say

By Ashley Strickland, CNN

(CNN) — Powerful solar activity released by the sun reached Earth Monday, causing colorful auroral displays and GPS issues for aircraft, according to the National Weather Service’s Space Weather Prediction Center, or SWPC.

A solar radiation storm, ranked at a level four out of five on a severity scale, was tracked by SWPC. The center designated the event as “the largest solar radiation storm in over 20 years.”

A solar radiation storm marks the release of intense, rapidly-moving charged particles toward Earth and can impact space launches, aviation and satellite operations. The last time severe solar radiation storm levels were observed was in October 2003, according to SWPC.

The Halloween space weather storms of October 2003 resulted in power outages in Sweden and damages to power transformers in South Africa, according to SWPC.

When solar radiation storms reach Earth, they can cause increased radiation exposure risks for astronauts in low-Earth orbit, like those aboard the International Space Station, as well as passengers on flights that are traveling polar routes.

SWPC notified airlines, NASA, the Federal Aviation Administration, the Federal Emergency Management Agency, the North American Electric Reliability Corporation and other operators ahead of the storm.

“We’ve been making all these phone calls to ensure that we are keeping all the critical technological infrastructure operators in the know of what’s happening,” said SWPC forecaster Shawn Dahl.

During increased radiation risk events, astronauts can move to parts of the space station that are better shielded, as they have during previous solar storms, like an extreme geomagnetic storm that occurred in May 2024.

Heightened radiation can also pose risks to satellites we rely on for communications and navigation.

During the May 2024 geomagnetic storm, tractor company John Deere reported that some customers reliant on GPS for precision farming experienced a disruption. But for the most part, power grid and satellite operators kept satellites in order and properly in orbit, and managed the buildup of intense geomagnetic currents on the grid systems.

While satellite operators were taking action Monday night, widespread technology impacts for the general public were not expected, said Ryan French, a solar physicist at the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder.

Anticipating auroras

Additionally, a severe geomagnetic storm reached Earth Monday at 2:20 p.m. ET, Dahl said. Such storms also have the ability to disrupt the electric power grid, according to SWPC.

Geomagnetic storms are caused by a coronal mass ejections (CMEs), or explosions of plasma and magnetic fields from the sun’s outer atmosphere.

When these outbursts are directed at Earth, they can cause major disturbances to Earth’s magnetic field, resulting in geomagnetic storms.

The coronal mass ejection, which launched from the sun on Sunday, was triggered by an X-class flare, the most intense type of solar flare. This marked the first major solar flare of the year, French said.

Increased solar activity causes auroras that dance around Earth’s poles, known as the northern lights, or aurora borealis, and southern lights, or aurora australis. When the energized particles from coronal mass ejections reach Earth’s magnetic field, they interact with gases in the atmosphere to create different colored lights in the sky.

Auroras experience short 20-minute bursts in activity called substorms. During these periods, the northern light are visible much further south than during the rest of the night, French said.

Forecasters initially thought auroras may be visible over much of the northern half of the US, and potentially as far south as Alabama and northern California.

But the arrangement of the magnetic field within the CME shapes which regions of Earth experience auroras and how much energy reaches the atmosphere, according to EarthSky.

The orientation of the storm once it reached Earth prevented widespread colorful displays from appearing in the skies over the US. However, images of powerfully vivid auroras were captured across Europe.

More flares from an active sunspot region are possible and any occurring within the next week have a good chance of producing further Earth-directed eruptions, French said.

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