Sun unleashes strongest solar flare of 2025, sparking radio blackouts across Africa and Europe

close up view of the sun firing off a colossal X5.1 solar flare on Nov. 11. — The X5.1-class eruption from sunspot AR4274 marks this year's most powerful solar flare and Earth is in the firing line. (Image credit: NOAA Space Weather Prediction Center)

gif animation of the X5.1 solar flare — Check out the ripples from the coronal wave lifting off during the X5.1 solar flare. (Image credit: NOAA Space Weather Prediction Center)

Editor's note: Wow, the northern lights put on a stunning display last night with auroras reported as far south as Mexico! See the best photos here in our wrap story. Conditions are also looking promising tonight as we await the CME impact from the X5.1 eruption. Check out our most recent article with the latest forecast and list of states that could see auroras tonight.

The eruption peaked at 5 a.m. EST (1000 GMT) from sunspot AR4274, which has been bursting with activity in recent days. The blast triggered strong (R3-level) radio blackouts across Africa and Europe, disrupting high-frequency radio communications on the sunlit side of Earth.

This outburst is the latest in a series of intense flares from AR4274, which also produced an X1.7 flare on Nov. 9 and an X1.2 on Nov. 10. Those flares were accompanied by coronal mass ejections (CMEs) that could combine and impact Earth overnight tonight, possibly triggering strong (G3) geomagnetic storm conditions and widespread auroras, according to NOAA's Space Weather Prediction Center. The CME released today could also join the party as it speeds toward Earth at 4.4 million mph. NOAA predicts the CME could impact Earth around midday on Nov. 12. With this third CME added to the mix, it's possible that we could experience severe (G4) geomagnetic storm conditions.

NASA M2M SWO estimate the speed of the CME at 1856 km/s - a very fast CME! The animation of the CME in Cor2 data is absolutely spectacular. Big, fast CME. Bulk headed for us. I think it is safe to say this will be one of the most impressive near side CMEs of the cycle (fingers… https://t.co/nkNhspZo9i pic.twitter.com/9dRXkiSAPSNovember 11, 2025

gif animation showing the CME lifting off from the sun after the X5.1 solar flare. — Coronagraph imagery shows the CME lifting off in rapid fashion this morning (Nov.11) (Image credit: NOAA Space Weather Prediction Center)

Solar flares are ranked by strength in five classes, A, B, C, M and X, with each step representing a tenfold increase in energy output. X-class solar flares are the most powerful kind and the number following the X describes the flare's intensity. At X5.1, this latest eruption sits toward the top of the scale.

The eruption sent a surge of X-rays and extreme ultraviolet radiation toward Earth, ionizing the upper atmosphere and causing widespread radio signal degradation. Strong (R3) radio blackouts were recorded over Africa and Europe.

graphic showing the strong radio blackouts across the sunlit portion of earth at the time of the eruption. the strongest blackouts are over africa and some of europe. — Radio blackouts associated with the X5.1 solar flare on Nov. 11. (Image credit: NOAA Space Weather Prediction Center)

This active region has become one of the most prolific solar flare producers of Solar Cycle 25, marking a fiery peak in what's already been an extraordinary week for solar activity.

The CME released this morning during the X5.1 solar flare is forecast to reach Earth on Nov. 12. According to NOAA, the CME could trigger severe (G4) geomagnetic storm conditions on Nov. 12.

graphic detailing the possible effects of the incoming CME as it could trigger strong G4 geomagnetic storm conditions on Nov. 12. — NOAA's CME alert issued Nov. 11. (Image credit: NOAA Space Weather Prediction Center)

Daisy Dobrijevic joined Space.com in February 2022, having previously worked as a staff writer for All About Space magazine. She completed an editorial internship with BBC Sky at Night Magazine and worked at the National Space Centre, communicating space science to the public.

Daisy holds a PhD in plant physiology and a Master's in Environmental Science. Based in Nottingham, U.K., she covers all things space, with a special focus on solar activity and space weather. She also has a keen interest in astrotourism and is always on the lookout for the next northern lights adventure.

She will be a guest speaker aboard HX's Solar Eclipse Expedition in August 2026 and will join Hurtigruten as an onboard astronomer for a northern lights sailing in January 2027.