Spectacular southern lights seen across Australia after ‘extreme’ solar storm

Aurora australis has lit up skies across southern Australia after an “extreme” geomagnetic solar storm.

Social media users in posted pictures of brightly coloured skies in Victoria, Tasmania, South Australia and across the Tasman in New Zealand.

However, much of New South Wales missed out on the spectacle due to heavy cloud and rain.

The Bureau of Meteorology has warned the storm that creates the beautiful auroras could also threaten infrastructure and essential services, including power supply.

• Sign up for Guardian Australia’s free morning and afternoon email newsletters for your daily news roundup

The BoM’s space weather forecasting centre said the storm’s effects reached Earth on Friday night and would continue to Sunday morning.

The BoM said the best time to see the aurora australis was between Saturday 10pm and Sunday 2am, from a dark spot with unobstructed views south.

On Wednesday and Thursday, there were four coronal mass ejections (CMEs) from the sun, meaning highly charged plasma erupted and streamed into space. When those charged particles, known as the solar wind, hit the Earth’s magnetic field, they create the stunning visual displays known as auroras.

“The last time a G5 geomagnetic storm was observed was in 2003,” the BoM said in a statement.

“The warning issued for this event informs government and critical infrastructure operators so they can take action to mitigate potential impacts on infrastructure and essential services.

“The bureau continues to monitor the situation and will provide updates of significant changes.”

Auroras were visible across Tasmania and South Australia on Saturday morning, along with other parts of the southern hemisphere.

“When G5 geomagnetic conditions occur, bright auroras will be visible at unusually low latitudes, including dark-sky locations near Sydney and Perth,” the BoM said.

“Auroras may also be visible from as far north as southern Queensland and other low-latitude locations.”

The bigger the storm, the closer to the equator the lights – normally only visible closer to Earth’s poles – appear.

The northern lights, aurora borealis, were also visible across large parts of Europe, including in the UK, on Saturday morning their time.

However, solar storms can also hit power grids, causing outages, and disrupt satellite services used for communications, global positioning, navigation, and timing services as well as high frequency radio waves.

The bureau forecast a G4 (severe) level event, a measure of global activity that refers to fluctuations in Earth’s magnetic field and ranges from G1 (minor) to G5 (extreme). According to the BoM’s website, the level hit G5 on Saturday morning, but could reduce to a G3 by Sunday.

“The solar wind environment is currently very enhanced. The solar wind speed is expected to be very strong,” the BoM’s website said. “There is currently a sequence of CMEs heading toward the Earth and further CME arrivals are expected.

“HF radio communication conditions are expected to be very poor.”