An image of the sun showing sunspot 3842
Photo by: Sansa
A strong geomagnetic storm is expected over the weekend and could disrupt communications and navigation systems, as well as potentially cause the reappearance of the Southern Lights over South African skies, the South African Space Agency (SANSA) warns.
The origin of this storm is a solar flare that erupted from sunspot 3842 on October 3.
"This is the strongest Earth-facing solar flare recorded by SANSA in the past seven years and measured X9.05. Solar flares are measured in five categories, A, B, C, M and X with X being the strongest," it points out.
SANSA adds that the X9 flare on October 3 impacted on high-frequency radio communications, resulting in a total radio blackout over the African region which lasted for up to 20 minutes.
SANSA has been monitoring sunspot region 3842 since September 29, when it appeared on the Sun's visible disk. It is about 1.5 times larger than the Earth’s surface area. The sunspot produced several significant solar flares and associated coronal mass ejections (CMEs), which are waves of charged energetic particles. These waves of energetic particles will impact Earth over the weekend, causing geomagnetic storms.
Geomagnetic conditions are expected to range from a G1 (minor) storm to a G3 (strong) with storm levels possibly reaching G4 (severe) storm throughout the day on October 5.
SANSA points out that South Africans had a rare glimpse of the Aurora Australis, or Southern Lights, on May 10 during what was a G5 (extreme) storm. 