Sun unleashes powerful X-class solar flare, knocking out radio signals across Australia

close up view of the sun emitting the giant solar flare in a fiery eruption

A powerful X1.9 solar flare from new sunspot AR4299 triggered strong radio blackouts, as giant sunspot AR4294 rotates into view with more activity likely. (Image credit: NASA / SDO and the AIA, EVE, and HMI science teams / helioviewer.org)

The sun kicked off December with a bang, unleashing a strong X1.9-class solar flare that briefly knocked out radio communications across Australia and parts of southeast Asia.

map showing strong radio blackouts across australia shortly after the x-flare eruption. — The X-1.9 solar flare sparked radio blackouts across Australia. (Image credit: NOAA Space Weather Prediction Center)

Coronagraph imagery from SOHO revealed a rapid partial-halo coronal mass ejection (CME), a release of plasma and magnetic field from the sun, blasting off the sun's northeast limb. Earth modelling confirms that the CME is not Earth-directed.

But the real story might be in the enormous sunspot region following closely behind this flare. AR4294, a sprawling, magnetically complex sunspot cluster, is now turning toward Earth. It is so complex that NOAA has split the region into three numbered groups because of its size and complexity. This is also the same area of the sun responsible for multiple X-class flares last month — and it's only grown even larger.

a detailed bulletin from NOAA reiterating what to expect this week from the large sunspot region rotating into view. — NOAA's Space Weather bulletin for the week of Dec. 1-5, 2025. (Image credit: NOAA Space Weather Prediction Center)

NOAA space weather forecasters anticipate a likely continuation of M-class solar flares and a slight chance of more X-flares between Dec. 1-3. While no Earth-directed CMEs have been detected, increased activity from AR4294 could change that in the days ahead, so watch this space!

Meanwhile, geomagnetic conditions are expected to stay mostly quiet until Dec. 3, when a negative-polarity coronal hole stream may bring minor (G1) geomagnetic storming.

Daisy Dobrijevic joined Space.com in February 2022 having previously worked for our sister publication All About Space magazine as a staff writer. Before joining us, Daisy completed an editorial internship with the BBC Sky at Night Magazine and worked at the National Space Centre in Leicester, U.K., where she enjoyed communicating space science to the public. In 2021, Daisy completed a PhD in plant physiology and also holds a Master's in Environmental Science, she is currently based in Nottingham, U.K. Daisy is passionate about all things space, with a penchant for solar activity and space weather. She has a strong interest in astrotourism and loves nothing more than a good northern lights chase!

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