A powerful solar flare erupted from the Sun on June 19, causing significant disruptions to radio communications across the Pacific region. The flare, classified as an X1.9 event, is the strongest recorded so far in 2025, according to NASA and the NOAA Space Weather Prediction Center.
The flare was emitted from active sunspot region AR4114 and peaked at approximately 7:50 p.m. Eastern Time. Experts report that the burst caused a temporary blackout of high-frequency (HF) radio signals below 25 MHz, primarily affecting aviation, maritime, and shortwave radio operations over the Pacific Ocean. There were no immediate reports of impact on GPS services or satellite operations, although further analysis is ongoing.
Earlier in the week, on June 17, the same sunspot produced another powerful X1.2-class flare that also resulted in radio signal loss in parts of North America. In both cases, the flares led to ionization in Earth’s upper atmosphere, affecting radio wave propagation. NASA and NOAA confirmed that while no major coronal mass ejection (CME) followed the June 19 flare, conditions are still being monitored for delayed solar particle emissions.
The current activity is part of an upward trend in Solar Cycle 25, which is expected to reach its maximum in mid-2025. AR4114 has been among the most active regions this month, producing several M-class flares in the days leading up to the X-class events. Scientists warn that additional eruptions are possible in the coming weeks.
Space weather experts emphasize that solar flares of this magnitude, while not harmful to humans on Earth, can disrupt critical systems such as long-distance radio, satellite communications, and navigation networks. Operators of such infrastructure are advised to remain alert to further advisories from the Space Weather Prediction Center.
The National Oceanic and Atmospheric Administration continues to monitor solar activity and has issued a Level R3 (strong) radio blackout alert for the June 19 event.
