Early Tuesday morning, NOAA’s Space Weather Prediction Center (SWPC) posted on X: “An S4 severe solar radiation storm is now in progress – this is the largest solar radiation storm in over 20 years. The last time S4 levels were observed was in October 2003."
But, it noted: “Potential effects are mainly limited to space launch, aviation, and satellite operations.”
The National Emergency Management Agency (Nema) said the coronal mass ejection arrived in Aotearoa about 8.30am on Tuesday, “and it is not expected to cause significant impacts for NZ”.
The agency had activated its Space Weather Science Advisory Panel, which had considered international space weather monitoring and forecasting agencies, as well as current information from the NZ-based monitoring network.
“On current conditions, the panel advises this event is not concerning for NZ and no significant impacts are expected. Nema and Transpower will continue to monitor the situation.”
A Transpower spokesperson said it was keeping an eye on the storm, but the threshold had not yet been met to make changes to the grid.
Large solar storms could send unwanted currents through the long electricity circuits which Transpower managed. When they reached transformers in stations or large hydroelectric dams, they could cause extensive damage.
“We have been closely monitoring the solar storm since the coronal mass ejection lifted off the sun on Sunday,” the spokesperson said.
“It arrived at 8.40am this morning resulting in geomagnetically induced currents (GICs) in our electricity transmission network, but these are within limits where mitigation actions are not needed.”
There was a contingency plan in place to switch out circuits to mitigate effects if needed, but there would be no impact on consumer electricity supply even if this was necessary.
The threat of disruption caused by solar storms has become increasingly understood by local agencies, and a number of them have plans in place. Nema simulated a G5 event in the Beehive bunker in November last year.
-RNZ
