The last in a series of three coronal mass ejections hit Earth on Wednesday, so experts are keeping an eye on geomagnetic storm potential

A massive solar flare unleashed November 11 was one of the strongest on record, experts say—and the Earth-based fallout from weather on our closest star isn’t done yet.

The flare—a powerful burst of radiation—was among the strongest in the sun’s current activity cycle, researchers say. It came from Region 4274, a complex sunspot with a strong magnetic field, according to the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (SWPC).

Key takeaway: Who cares about space weather?

You may not give much thought to space weather generated on the sun. But just because it’s not always visible doesn’t mean it’s insignificant: Space weather can affect everything from radio communications to GPS systems, aviation and the power grid. Experts in space weather are constantly monitoring solar threats and communicating them to those in government, industry and other sectors.

Tuesday’s flare was the strongest of the year so far—and the sixth largest in the current solar cycle, SWPC service coordinator Shawn Dahl tells AccuWeather’s Emilee Speck. It was “perhaps among the top 39 solar flares recorded in the space age,” Dahl tells the outlet.

In October 2024, NASA and NOAA announced that the sun had reached its solar maximum—the most active phase of its roughly 11-year-long activity cycle. That month, the sun released its largest flare of the cycle, classified X9.0 on the agency’s space weather scale. The center measures the potential of such flares to disrupt radio signals on Earth’s surface, sorting them into categories, with each being ten times stronger than the last: A, B, C, M and X.

Yesterday’s flare, by contrast, measured an X5.1—putting it between “strong” and “severe” on the agency’s space weather scale. Forbes’ Jamie Carter reports that while the solar maximum has been hypothesized to be over, yesterday’s extreme flare might mean the current solar cycle has peaked twice.

Space weather also contributes to charging the auroras typically seen around the poles—and, in extreme cases, super-charging them to cover a much wider range than usual. The powerful solar activity this week brought the northern lights as far south as Florida and Mexico from Tuesday night into Wednesday. And another light show might happen Wednesday night.

Though solar flares are the solar system’s most powerful explosions, it’s another kind of eruption—a coronal mass ejection (CME)—that more strongly powers these lights. These clouds of electrically charged gas and magnetic fields from the sun can deliver energy to atoms of gas in our atmosphere. As the gases release the excess energy, they glow in brilliant colors. 

On November 10, NOAA warned of impending geomagnetic storms related to a series of CMEs expected to influence Earth between November 11 and November 13. Earth’s magnetic field and atmosphere protect life on the planet’s surface from dangerous radiation, but solar activity can still impact satellites and spacecraft. Such storms disturb the planet’s own magnetic field, which can cause radio blackouts, power outages and auroras. 

“SWPC forecasters believe that Earth was and is being impacted by the first two of three anticipated CME arrivals,” the agency wrote on its website early Wednesday morning. Though the “final and most energetic” of the CMEs was yet to arrive at the time, the agency added, it hit Earth on Wednesday, reports Spaceweather.com.

The first two ejections brought Tuesday night’s fantastic auroras. The third CME may make auroras “visible over much of the northern half of the country [U.S.], and maybe as far south as Alabama to northern California,” the SWPC predicts. To get the best chance at spotting them, find a dark area away from light pollution and look toward the northern skies. Even if you don’t see the glow, try taking a picture with your phone’s night mode—our devices are more sensitive to these lights than human eyes are.

The third CME could be even more powerful than the last two, Dahl tells NPR’s Rachel Treisman and Mansee Khurana. “It was traveling significantly faster than these other two, and we think that’s going to pack even a stronger punch than what we’ve already experienced.” Still, its potential impacts are not fully known. So, keep an eye on aurora forecasts and stay tuned for the possibility of more tumultuous space weather to come.