Record S4 Radiation Storm: Solar Proton Flux Near Earth Surpasses 2003 Levels for the First Time in 22 Years
Record S4 Radiation Storm: Solar Proton Flux Near Earth Surpasses 2003 Levels for the First Time in 22 Years.
January 19–20, 2026, marks a rare event unfolding near Earth: a severe solar radiation storm at level S4 on the NOAA scale. This is the first such intense event in two solar cycles—approximately 22 years.
The Laboratory of Solar Astronomy at the Space Research Institute of the Russian Academy of Sciences (IKI RAN) reported that the solar proton flux with energy >10 MeV exceeded 10,000 pfu (proton flux units), reaching 37,000 pfu by the evening of January 19. This surpasses the levels recorded during the famous X17.2 flare on October 28, 2003, setting an absolute record for the 21st century. The historical peak (~40,000 pfu) was registered in the 20th century.
"A record value for the 21st century has been reached," scientists from IKI RAN noted in their laboratory's Telegram channel.
The U.S. National Oceanic and Atmospheric Administration (NOAA) confirmed that an S4 Severe Solar Radiation Storm has been ongoing since January 19—the strongest radiation storm since 2003. Level S5 (extreme) has never been observed in recorded history and remains theoretical.
Causes and Consequences
The event was triggered by a powerful X1.9-class solar flare on January 18 and a subsequent coronal mass ejection (CME). High proton fluxes pose risks to:
- satellites (electronics malfunctions, accelerated solar panel degradation),
- astronauts and polar flight crews (increased radiation exposure),
- high-frequency radio communications in polar regions.
There is no danger to people on Earth’s surface—the planet’s magnetic field and atmosphere provide reliable protection.
A strong geomagnetic storm at level G4 is also currently ongoing, resulting in vivid auroras visible at mid-latitudes.
Scientists emphasize that this intense solar activity reflects the current peak of Solar Cycle 25, which has proven unexpectedly vigorous.
Stay updated via official sources:
Laboratory of Solar Astronomy