The South African National Space Agency’s (SANSA’s) Space Weather Centre (part of the SANSA Space Science division and based at Hermanus in the Western Cape) has warned that the current geomagnetic storm hitting the Earth would likely continue until Friday. The storm was the strongest of its type so far this year.

Geomagnetic storms affect and can disrupt technological systems, particularly global navigation satellite systems (GNSS, popularly known as GPS), but also communication systems, electrical power grids and electronic systems. Disruptions to GNSS, in turn, affect the aviation, maritime and drone sectors.

These storms also create spectacular auroras over the north and south polar regions. (Because of South Africa’s distance from the South Pole, auroras are unlikely to be seen from here, but with this storm it is not impossible, although a dark and cloudless night is needed to observe them.)

Geomagnetic storms are classified from G1 (minor), to G5 (extreme). The SANSA Space Weather Centre is forecasting that the current storm will oscillate between G1 and G4 (which indicates severe), before it fades away on Friday. It hit G4 early on Wednesday morning, South African time.

The storm was triggered by three strong solar flares (classified as X-class). “A solar flare is a sudden burst of light from the Sun and takes about eight minutes to reach Earth,” explained SANSA. These solar flares were observed on Sunday (November 9), Monday and Tuesday. Accompanying all three of the solar flares were coronal mass ejections (CMEs), which are “clouds of charged particles hurled into space”, and which hit the Earth.

It was the CMEs which triggered the geomagnetic storm. The storm was the result of the charged particles, which composed the CMEs, interacting with the Earth’s magnetic field.

“SANSA monitors the impact of the storm as it arrives at Earth through a network of ground-based instruments over the African continent, the Southern Ocean and Antarctica,” explained the agency. “SANSA works with space weather centres across the globe to monitor these storms. There is no way to prevent geomagnetic storms from impacting Earth, however, industries working with these technological systems can implement mitigating steps to minimise the impact.”