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Sun Unleashes Strongest Flare of 2025, Causing Global Radio Blackouts

Sun Unleashes Strongest Flare of 2025, Causing Global Radio Blackouts

On Nov. 11, 2025, the Sun released an X5.1-class flare from sunspot AR4274, the strongest of the year.

Written by Gadgets 360 Staff | Updated: 13 November 2025 21:24 IST

Sun Unleashes Strongest Flare of 2025, Causing Global Radio Blackouts

Photo Credit: NOAA

X5.1 solar flare caused radio blackouts; geomagnetic storm warning issued by NOAA

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Highlights

Sun emits X5.1 flare, strongest of 2025 so far
R3-level blackout hits Africa and Europe’s radio links
CME may spark major geomagnetic storm, NOAA warns

On November 11, 2025, the Sun unleashed an X5.1-class flare — the strongest of the year — from active region AR4274. These intense bursts of solar energy (X-class being the top level) hit Earth's daytime side almost instantly, flooding the upper atmosphere with ionising radiation. The sudden surge of X-rays and ultraviolet light caused widespread shortwave (HF) radio blackouts across Africa and Europe, momentarily interrupting communications on the sunlit side of Earth.

Eruption of a Major Solar Flare

According to a report from SpaceX.com, at 5 a.m. EST on November 11, 2025, the X5.1 flare will go into a peak at sunspot AR4274, which is very active and already has emitted X1.7 and X1.2-level flares on November 9-10. The Nov. 11 explosion was especially severe due to the X-class of solar eruptions being the strongest. An ejection known as coronal mass ejection (CME) was also shot into space towards the Earth. It was estimated by NOAA that the CME could hit Earth on the 12th of November and lead to a massive geomagnetic storm.

Earth Impacts: Radio Blackouts and Auroras

The UV and X-rays of the flare ionised the upper atmosphere of the Earth, and the radio signals of shortwaves (HF) became absorbed. According to the Space Weather Prediction Center of NOAA, in the sunny side, HF radio contact over a long distance was lost because of the so-called strong (R3-level) radio blackouts. NOAA defined an R3 event as a radio-blackout manifested in a broad area that is not sustained over a long period (approximately 1 hour). The coronal mass ejection (CME) of a flare was forecasted to hit Earth around November 12, potentially leading to a major geomagnetic storm and bright auroras at very low latitudes.

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