Overview
- Late on Jan. 19 (MSK), the plasma cloud from the Jan. 18 X1.95 flare hit Earth, with L1‑to‑planet transit indicating a speed of about 1,700 km/s.
- A level S4 solar radiation storm is underway near Earth for the first time in roughly 24 years, with proton flux surpassing 10,000 units and peaking around 14,000.
- Labs report radiation exposure to spacecraft about 50 times above the hazard threshold and >10 MeV proton densities more than 1,000 times higher than a day earlier.
- Geomagnetic storms of G3–G4 strength are forecast, with a small chance of G5, and auroras could extend to latitudes near 50 degrees.
- The flare originated from active region 4341 near the solar disk center, and researchers note the unusually intense proton event relative to overall low solar activity, with additional strong flares possible on Jan. 19–20.