Solar Storms and the Power Grid: The Real Risk and How to Prepare

Quick answer: Severe solar storms can disturb power grids, GPS and radio. In May 2024, the strongest geomagnetic storm in over 20 years reached the top G5 level, yet the North American grid stayed stable because operators had warning and followed set procedures. The UK government puts the chance of a severe space weather event in the next five years at 5–25%, with possible regional power cuts. Preparing for a solar storm is the same as preparing for any power cut: light, water, food, cash, a radio and phone power for a few days.

What space weather is

Space weather describes conditions in space, driven by the Sun, that can affect technology on Earth. The Sun throws out solar flares, bursts of charged particles and huge clouds of magnetised gas called coronal mass ejections (CMEs).

The UK Met Office says energy from a flare reaches Earth in just over eight minutes, while CMEs can take days. When a CME hits Earth’s magnetic field, it can cause a geomagnetic storm. Strong storms can push extra electric currents into long power lines and transformers, scramble satellite navigation and disrupt high-frequency radio.

The US Space Weather Prediction Center (SWPC), part of NOAA, rates geomagnetic storms from G1 (minor) to G5 (extreme).

Level	What NOAA says can happen to power systems	How often (average per 11-year solar cycle)
G4 (severe)	Possible widespread voltage control problems; some protective systems may trip key equipment off the grid	About 100 storms (60 days)
G5 (extreme)	Widespread voltage control and protective system problems; some grids may collapse or black out; transformers may be damaged	About 4 storms (4 days)

The May 2024 storm

Between 10 and 12 May 2024, several CMEs hit Earth. The North American Electric Reliability Corporation (NERC) calls it the largest geomagnetic disturbance in over two decades. Conditions swung between G3 and G5 over three days. It was the first G5 storm in about 20 years.

NOAA’s SWPC warned grid operators in advance so they could take protective action. NERC’s review, published in January 2026, found that operators followed their storm procedures and the bulk power system remained stable throughout. Operators did see isolated effects on some transformers, voltage equipment, circuit breakers and filters.

GPS was hit harder. NOAA’s SWPC told Fox Weather that GPS-guided tractors in the US, normally accurate to about a centimetre, were off by around 3 metres (10 feet). Some farmers stopped planting until conditions settled.

For most people, the main sign of the storm was the aurora, seen much further south than usual, including in southern parts of the UK.

Notable space weather in 2025 and 2026

NASA and NOAA announced on 15 October 2024 that the Sun had reached the maximum period of its 11-year cycle. Since then, there have been more strong events.

November 2025: An X5.1 solar flare erupted on 11 November. SWPC reported G4 (severe) storm levels at 01:20 UTC on 12 November.
January 2026: G4 storm levels were reached at 19:38 UTC on 19 January. At the same time, SWPC reported an S4 (severe) solar radiation storm, the most intense since October 2003. SWPC said the effects were mainly on flights over polar routes, satellites and high-frequency radio in polar regions. The Met Office said auroras were seen as far south as northern Italy.

In January 2026, the Met Office said the Sun is now in the declining phase of its cycle. It also noted that some of the strongest space weather events in the past have come after solar maximum. So the risk does not simply end as sunspots fade.

What agencies say about the risk

A real but rare risk to the grid

The best-known grid failure from space weather happened on 13 March 1989, when a geomagnetic storm tripped transmission lines in Québec, Canada. According to Australia’s Bureau of Meteorology, restoring service took more than nine hours.

The UK National Risk Register

The UK’s National Risk Register 2025 plans for a “reasonable worst case” similar in scale to the Carrington storm of 1859, lasting one to two weeks. Possible effects include:

regional power disruption
loss or disruption of satellite navigation such as GPS
disruption to some communications, including satellite links and high-frequency radio
disruption to aviation

The register says power lost because safety systems trip in towns and cities could be restored within hours. If transformers needed replacing in remote coastal areas, recovery could take several months. Satellite and GPS services could take several days to recover.

The UK government assessed the chance of a severe space weather event within five years at 5–25%. In March 2026, the National Audit Office reviewed the UK’s readiness. It said roles and responsibilities for managing the risk were still unclear and recommended clearer accountability.

How to prepare your household

The good news is that you do not need special solar storm gear. Ready.gov explains that space weather can cause power cuts, which can then affect water, food storage, heating, phones, transport and fuel. The same supplies cover all of these.

Before a storm (or any time):

Build a basic kit with water, food, torches and batteries. Our 72-hour emergency kit guide has a full list.
Keep power banks and phone chargers ready.
Keep your car’s fuel tank at least half full, as Ready.gov suggests.
Learn how to open an electric garage door or gate by hand.
Ask your pharmacist how to store medicines that need a fridge.
Keep a paper map, since satellite navigation may be unreliable during a strong storm.
Keep some cash at home in case card payments are disrupted.

During a storm warning or power cut:

Follow official alerts on radio and TV.
Ready.gov advises using less electricity to help avoid rolling blackouts.
Unplug appliances if local officials ask you to.
Use the phone only when needed, so lines stay free for emergencies.

After the power returns:

Throw away perishable food that has been above 4 °C (40 °F) for 2 hours or more. Never taste food to check it.

For fridge timings, safe lighting and avoiding carbon monoxide, read our power outage preparation guide. To see how long your home could manage without mains power, check how many days your household would last.

Checklist

Forecasters at NOAA, the Met Office and other agencies watch the Sun closely, and grid operators get warnings before storms arrive. Prepare for a power cut, enjoy the aurora, and follow your local authorities’ advice if a severe storm is forecast.

Sources & further reading

Every fact in this post was checked against the sources listed above on 1 November 2026. Advice changes: always follow your local authorities.