Electron 2 MeV Integral Flux Alert issued on September 3

An Electron 2 MeV Integral Flux Alert was issued on September 3, 2026, after observations indicated that the electron flux at energies greater than 2 MeV exceeded 1,000 particles per square centimeter per second per steradian (pfu). The alert remains in effect, and the maximum observed 2 MeV electron flux reached 1,239 pfu on September 3, 2026 at 10:20 UTC.

Elevated electron flux levels of this magnitude can pose increased risk to spacecraft operations, including potential surface charging and deep dielectric charging events on satellites in geostationary and other high-altitude orbits. These conditions may also result in increased background noise for some satellite-borne instruments, but no ground-level or human health effects are expected.

The official NOAA SWPC forecast notes that the greater than 2 MeV electron flux is expected to remain at high levels through September 3, before decreasing to normal to moderate levels on September 4 and 5, 2026. No significant solar wind or geomagnetic disturbances have been reported at this time.