X1.9 flare’s CME sparks S4 radiation storm and G4 geomagnetic storm — widespread satellite, GPS and HF impacts reported

The event produced the strongest S4 radiation and G4 geomagnetic combination in over 20 years, reinforcing recent observations of unusually large radiation spikes by space sensors (UK probe detection).

NOAA and operators report satellite anomalies, GPS degradation and HF radio outages — impacts that have previously translated to significant GNSS disruption and economic loss in critical sectors (GNSS loss and economic impact) and were forewarned in earlier CME forecasts (CME strike forecasts).

The geomagnetic activity produced aurora at unusually low latitudes and elevated space‑radiation conditions at flight altitudes, underscoring operational exposure for polar/high‑latitude routings and for crews/passengers on high‑altitude flights (radiation at flight altitudes) and matching cockpit observations from past G4 events (airline aurora footage).