Washington: The National Weather Space Weather Prediction Centre (SWPC) has issued a 'severe geomagnetic storm watch' for this weekend starting from Friday, which is the first time such watch has been issued in nearly 20 years. The alert was issued after five earth-directed coronal mass ejections (CMEs) were observed and expected to arrive by Friday.
Several strong flares have been observed over the past few days by scientists and were associated with a large and magnetically complex sunspot cluster, 16 times the diameter of the Earth. Additional solar activity is also expected from the region. The SWPC has classified this as an "unusual event" and predicted that this may persist till Sunday.
The SWPC predicted that a severe G4 geomagnetic storm could emerge as early as Friday after days of solar activity. The solar storm, which will primarily impact the United States and surrounding countries, is expected to disrupt several services. The SWPC has already notified operators so they can take protective action.
What are geomagnetic storms?
The National Oceanic and Atmospheric Administration (NOAA) refers to a geomagnetic storm as a major disturbance of the Earth's magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding the Earth. These storms result from variations in the solar wind that produces major changes in the currents, plasmas, and fields in Earth’s magnetosphere.
Geomagnetic storms emerge from solar CMEs, which are explosions of plasma and magnetic fields from the sun’s corona. These explosions cause geomagnetic storms when they are directed towards the Earth. However, geomagnetic storms are not considered dangerous to human bodies. The last geomagnetic storm watch was observed in January 2005.
The G-scale is a measure of global geomagnetic activity, which refers to fluctuations in Earth's magnetic field across the globe. The G-scale ranges from G1 (minor) to G5 (extreme). If G4 geomagnetic conditions occur, bright auroras will be visible at unusually low latitudes. A severe geomagnetic storm includes the potential for aurora to be seen as far south as Alabama and Northern California.
How will the impact services on Earth?
According to the SWPC, geopolitical storms can impact infrastructure in near-Earth orbit and on Earth’s surface, potentially disrupting communications, the electric power grid, navigation, radio and satellite operations. According to NOAA, they can also cause some protective systems to "trip out key assets from the grid," as well as orientation issues for spacecraft.
Disruptions are likely in:
- Navigation systems
- Internet
- Power grids
- Satellites
- Radio communications
While 100 severe geomagnetic storms occur in every solar cycle, only three “severe” geomagnetic storms have been observed since the current solar cycle began in Dec. 2019. The last G4 storm hit Earth in March, and the last G5 storm hit in Oct. 2003, causing power outages in Sweden, according to SWPC.
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