The geomagnetic storm could cause minor fluctuations in the power grid, radio blackouts and confuse spacecraft systems. Space weather forecasters have warned of a “Moderate G2 storm” between Saturday, March 23, and Sunday, March 24. The solar storm comes in the wake of a burst of plasma and energy known as Coronal Mass Ejection (CME) escaping the Sun. The US-based Space Weather Prediction Centre (SWPC) has linked the CME to powerful solar flare observed on March 20.
The SWPC said in its warning: “A G2 moderate geomagnetic storm watch is in effect for the March 23, 2019, UTC day due to anticipated CME arrival.
“An asymmetric halo CME was observed in SOHO/LASCO coronagraph imagery and initial analysis of the CME in both LASCO and STEREO-A coronagraph imagery shows an Earth-directed component is likely.
“The CME was associated with a C4 flare on March 20, 2019, 11.18am UTC (7.18am EDT).”
Geomagnetic storms are the result of solar particles and streams of plasma striking the Earth’s magnetic field at high speed.
At their weakest, Minor G1 storms can cause weak fluctuations in the power grid and confuse migratory animals.
The strongest storms, Extreme G5 events, have been known to cause total power blackouts, wipe out satellites and create Northern Lights as far down south as Florida or Texas.
The SWPC explained: “The largest storms that result from these conditions are associated with solar coronal mass ejections where a billion tons or so of plasma from the sun, with its embedded magnetic field, arrives at Earth.
“CMEs typically take several days to arrive at Earth, but have been observed, for some of the most intense storms, to arrive in as short as 18 hours.”
In its space weather forecast for the weekend, the SWPC said aurora effects are likely to extend south from the polar regions to the northernmost US states.
These include South Dakota, Montana, Washington, New York, Main and Pennsylvania.
On the three-day forecast track, the SWPC does not expect any significant solar radiation storms to form.
But there is a slight possibility of minor radio blackouts between Friday, March 22, and Sunday, March 24.
The SWPC said: “During storms, the currents in the ionosphere, as well as the energetic particles that precipitate into the ionosphere add energy in the form of heat that can increase the density and distribution of density in the upper atmosphere, causing extra drag on satellites in low-earth orbit.
“The local heating also creates strong horizontal variations in the ionospheric density that can modify the path of radio signals and create errors in the positioning information provided by GPS.
“While the storms create beautiful aurora, they also can disrupt navigation systems such as the Global Navigation Satellite System and create harmful geomagnetic induced currents in the power grid and pipelines.”
Aurora effects are caused by solar particles exciting gas molecules in the Earth’s atmosphere to the point where they start to give of multi-coloured hues of light.