Strongest Solar Radiation Storm Since 2003 Triggers Global Monitoring

The Sun has released its most powerful solar radiation storm in more than 20 years, prompting global monitoring efforts as charged particles move toward Earth and raise the prospect of vivid auroral displays and limited disruption to satellite-dependent systems.

The US National Weather Service’s Space Weather Prediction Center (SWPC) said the event has been classified as an S4, or “severe,” storm on a five-point scale—the highest level observed since October 2003. In a statement posted on social media, the agency said the primary impacts are expected to be confined to space-based and high-altitude operations, including satellite systems, aviation—particularly flights on polar routes—and space launches. The 2003 “Halloween” solar storms, which reached similar levels, were linked to power outages in Sweden and damage to transformers in South Africa.

Solar radiation storms occur when the Sun releases high-energy charged particles that travel rapidly through space. When they reach Earth, they can increase radiation exposure for astronauts aboard the International Space Station and for passengers and crew on high-latitude flights. SWPC said it has notified airlines, NASA, the Federal Aviation Administration, emergency management agencies and power grid operators to ensure precautionary measures are in place. Astronauts can reduce exposure by moving to more heavily shielded areas of the space station, a step taken during previous major solar events.

Satellites used for communications, navigation and Earth observation may also face heightened risk. During a major geomagnetic storm in May 2024, some GPS-dependent activities—including precision agriculture—experienced temporary disruption, although power grids and satellite operators were largely able to manage the effects. Experts say a similar pattern is likely this time. “Widespread impacts for the general public are not expected,” said Ryan French, a solar physicist at the University of Colorado Boulder, though satellite operators may need to take short-term protective action.

Alongside the radiation storm, a severe geomagnetic storm reached Earth on Monday afternoon, driven by a coronal mass ejection—an explosion of plasma and magnetic fields—from the Sun’s outer atmosphere. The eruption was triggered by an X-class solar flare, the most intense category, and marked the first major flare of the year. Such geomagnetic storms can disturb Earth’s magnetic field and, in rare cases, affect power grids.

The increased solar activity is also expected to produce auroras well beyond their usual polar regions. According to SWPC, the northern lights could be visible across much of the northern United States and potentially as far south as Alabama and northern California, depending on local weather conditions. Meteorologists said clearer skies across parts of the Midwest and Pacific Northwest could offer particularly good viewing opportunities.

Scientists cautioned that the Sun remains active and that further flares from the same sunspot region are possible in the coming days. Any additional eruptions directed toward Earth could prolong elevated space weather conditions, keeping satellite operators, aviation authorities and power utilities on heightened alert.

Via CNN/Space