S2 – Moderate Solar Radiation Storm Alert issued on January 19

An S2 – Moderate Solar Radiation Storm Alert was issued by NOAA SWPC on January 19, 2026. The alert came into effect at 04:40 UTC, following an increase in 10 MeV proton flux levels exceeding 100 pfu as detected by space weather monitoring systems.

According to the official alert, potential impacts include small, increased radiation exposures for passengers and crew on high latitude, high altitude flights. Infrequent single-event upsets to satellites are possible, and small effects on polar high-frequency radio propagation could result in fades at lower frequencies.

This Solar Radiation Storm was triggered by an X1.9-class solar flare that peaked at 18:09 UTC on January 18, 2026, from Active Region 4341 (S11E24). The flare was accompanied by both Type II and Type IV radio sweeps and a significant radio burst, as well as a full halo coronal mass ejection first observed shortly after the flare.