Rare Severe Solar Storm Brings Northern Lights to Parts of California

A rare S4-level solar storm brought the Northern Lights into parts of Northern California, marking the strongest solar radiation event of its kind in more than two decades.

The Northern Lights, which typically occur near polar regions, was been visible in parts of Northern California from January 19 through January 20, 2026.

According to the U.S. National Oceanic and Atmospheric Administration (NOAA), the rare event was triggered by severe space weather that began on January 18, 2026. A coronal mass ejection, or CME, is a large burst of solar material and magnetic fields released from the Sun.

The CME was associated with an X1.9 solar flare and classified as R3, or strong, on NOAA’s radio blackout scale, indicating a powerful energy release.

The CME arrived late on January 19 into early January 20, triggering heightened geomagnetic activity around Earth.

According to NOAA updates, geomagnetic activity gradually weakened to between G1 and G3 levels after peaking overnight. This comes after the G4 levels that remained overnight on January 20. Residual effects from the CME mean that minor geomagnetic activity remains possible into January 21.

Final video update: CME passage continues, but weakening; back down to G1-G3 levels after more G4 overnight; G1 possible again tonight due to residual CME influences and CH HSS effects; & back down to S1-S2 levels. Keep space weather aware at https://t.co/TV7Yw6Lq1Y pic.twitter.com/N4MkBc3NP9

— NOAA Space Weather Prediction Center (@NWSSWPC) January 20, 2026

Earlier, NOAA said a severe G4 geomagnetic storm conditions were recorded again at 10:21 UTC.

Update: G4 (Severe) geomagnetic storm levels were reached again at 10:21 UTC (05:21 EST).

— NOAA Space Weather Prediction Center (@NWSSWPC) January 20, 2026

While auroras can be visually striking, NOAA warned that severe geomagnetic storms can disrupt satellites, affect GPS accuracy, and interfere with radio communications.

In addition, satellite systems can also experience problems due to increased radiation and magnetic disturbances. NOAA emphasized that there is no direct danger to people on the ground, as Earth’s atmosphere provides strong protection from harmful solar radiation.

The last time a solar radiation storm of this magnitude was recorded was in October 2003, during the so-called “Halloween solar storms,” according to NOAA.

During that event, a series of massive solar eruptions produced the last recorded S4-level solar radiation storm. Those storms caused widespread technological disruptions, including satellite anomalies, GPS issues, and power system problems in some regions. 

NOAA’s Space Weather Prediction Center continues to monitor solar activity and advises the public to follow official forecasts, noting that aurora visibility depends on local conditions such as cloud cover and light pollution.