Surprise X-class solar flare from emerging sunspot triggers radio blackouts across the Americas

The sun has somewhat surprised forecasters today with a dramatic X-class solar flare from a newly emerging sunspot region.

The intense solar flare originated from sunspot region AR4046 and was accompanied by a spectacular filament eruption and coronal mass ejection (CME) — an expulsion of plasma and magnetic field from the sun.

When CMEs (also known as solar storms) hit Earth's magnetosphere they can trigger active geomagnetic storm conditions resulting in impressive auroras. However, the CME in this event is unlikely to impact Earth due to the current location of the sunspot region. "The CME that followed may not be Earth-directed; the region was too close to the east limb," solar physicist Halo CME wrote in a post on X.

Space weather forecasters and aurora chasers are keeping a close eye on AR4046 as it crackles with solar activity.

"The flare source region will rotate to face Earth in the coming week. Further strong solar activity is likely!" solar astrophysicist Ryan French wrote in a post on X.

The region will rotate to face Earth next week, and any coronal mass ejection (CME) released at that time will be more likely to impact our planet, potentially triggering geomagnetic storms and dazzling auroras.

What are solar flares?

Solar flares release powerful bursts of electromagnetic radiation and are classified into five categories: A, B, C, M, and X. Each level represents a tenfold increase in intensity. A-class flares are the weakest and have little effect on Earth, while X-class flares are the strongest, capable of disrupting satellites and causing radio blackouts.

Within each category, a numerical rating (e.g., X1, X2, X10) further defines the flare's strength. The recent X-class solar flare clocked in at X1.1, placing it at the lower end of the X-class category.

Radio blackouts

After an X-class solar flare erupted, shortwave radio blackouts were detected across the Americas — the sunlit side of Earth at the time. These disruptions, common during intense solar activity, occur when the flare releases X-rays and extreme ultraviolet radiation into space.

Traveling at the speed of light, this radiation reaches Earth almost instantly, ionizing the upper atmosphere. The increased ionization alters atmospheric density, impacting high-frequency shortwave radio signals used for long-distance communication. As these signals pass through the charged layers, energy loss from collisions with electrons can weaken or even fully absorb transmissions, leading to radio blackouts.