South Africans were treated to a rare celestial spectacle this week after a severe geomagnetic storm lit up parts of the night sky and briefly made the Southern Lights visible as far north as the Western Cape, reports Cape {town} Etc.
According to the South African National Space Agency (SANSA), a coronal mass ejection (CME) produced by a long-duration X1.9 solar flare on Sunday, 18 January, reached Earth earlier than expected late on Monday evening, 19 January. The impact triggered escalating geomagnetic activity to G4 (severe) storm levels, with SANSA confirming that conditions intensified rapidly after arrival.
In an update issued at 11:45am on Tuesday, SANSA said the CME reached Earth at 9:15pm on Monday, triggering escalating geomagnetic activity that initially peaked at G2 (moderate) levels before intensifying to G4 (severe) storm levels as conditions strengthened on Tuesday morning.
The agency noted that ‘several photographers managed to capture images of the Southern Lights during the G4/severe storm conditions’, including striking photographs taken from Gansbaai in the Western Cape.
While auroras are common closer to the South Pole, sightings in South Africa are unusual due to the country’s distance from the auroral oval, indicating that for photographers who stayed up late on Monday evening, faint red and green glows on the horizon marked a rare and picturesque reward as the storm peaked.
In its statement, SANSA explained that the storm was driven not by the solar flare itself, but by the associated CME, which is a vast cloud of charged plasma hurled from the sun. When this cloud collided with Earth’s magnetic field, it caused widespread disturbance, measured using the planetary K-index, a global scale ranging from 0 to 9.
Local instruments at SANSA’s Hermanus Space Weather Centre recorded very high K-index values, indicating intense geomagnetic activity.
SANSA also confirmed that geomagnetic conditions remained elevated throughout Tuesday, fluctuating between G1 (minor) and G3 (strong) levels.
Excitement around the rare Southern Lights display quickly spread across social media as space weather watchers flagged the intensity of the event in real time. In an alert shared late on Tuesday evening, We Are South Africans issued an alert, citing data from GaiaSX, that ‘The G2-3 geomagnetic storm, with substorms peaking at Kp8 and a baseline of Kp7, is driven by a strongly favourable southward magnetic field at -13 Bz’.
‘The spectacle continues to amaze observers across the region. This will likely continue for the entire evening until early morning!’ it added.
Although geomagnetic storms are largely invisible to the naked eye, SANSA warned that their impacts are more keenly felt through technology. Potential effects included disturbances to satellite navigation systems such as:
- GPS
- Fluctuations in power grids
- Disruptions to high-frequency radio communications
- Increased atmospheric drag on low-Earth orbit satellites
The aviation sector, in particular, was advised to monitor conditions closely as strong solar winds – reaching speeds of around 900kph – could increase radiation exposure on high-altitude and polar routes.
SANSA concluded that it would continue to monitor the storm in real time, updating space weather data every three hours via its Space Weather Centre in Hermanus. Industries experiencing technological disruptions during the storm period are urged to report incidents to SANSA for further investigation.
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Picture: South African National Space Agency
