On Monday afternoon Earth was slammed by severe solar storm, which increased the chances of fluctuations in the power grid and GPS. The storm threatens to disrupt electricity supplies to millions of homes and businesses.

Generators and transmission companies were alerted on Monday by PJM Interconnection, which coordinates power to 61 million people across 13 US states and the District of Columbia. Similar warnings are being issued by controllers across the United States and Canada.

Efforts are being made to stabilize the grids as strong electromagnetic radiation emitted from the sun interacts with the Earth's own magnetic field. This provokes freak currents across the electricity transmission network.

The solar storm was categorized as severe early Tuesday by the US government's Space Weather Prediction Center (SWPC).

On March 13-14, 1989, a geomagnetic storm induced severe currents on high voltage power lines near the US-Canadian border. It knocked out the entire Hydro-Quebec power grid in just 92 seconds.

Relay transmission lines and generation units were automatically disconnected to protect the equipment from serious damage. Power was restored to 83% of affected customers within nine hours of the system's collapse.

However, 1989 storm damaged two large generator step-up transformers. Industry executives and regulators consider that high-voltage transformers are being threatened as networks carry only a limited stock of spares and it could take months to manufacture, deliver and install replacements.

If an extreme storm damages dozens or even hundreds of high-voltage transformers over a large area it would not be possible to replace them all quickly.

The Space Weather Prediction Center uses a series of satellites between the Sun and the Earth to identify eruptions and estimate the timing and severity of storms arriving on Earth.