S3 – Strong Solar Radiation Storm Alert issued on January 19

An S3 – Strong Solar Radiation Storm Alert was issued on January 19, 2026, after the 10 MeV proton integral flux exceeded 1,000 pfu. The alert began at 10:20 UTC and marks a significant increase in solar radiation levels.

Potential impacts from this event include increased radiation exposure for passengers and crew on high latitude, high altitude flights. Astronauts performing extra-vehicular activities (EVA) are also exposed to elevated radiation levels. Spacecraft may encounter single-event upsets in satellite operations, noise in imaging systems, and a slight reduction in solar panel efficiency. Additionally, users may experience degraded or sporadically blacked-out polar high frequency (HF) radio propagation.

This alert follows high solar activity, notably an X1.9-class solar flare that peaked at 18:09 UTC on January 18, 2026, from solar Region 4341 (S11E24). The flare was accompanied by Type II and Type IV radio sweeps and a full-halo coronal mass ejection (CME), contributing to elevated proton flux levels now being observed.