- Solar flares and plasma eruptions are common, and sometimes big enough to wreak havoc on Earth.
- Eruptions on the sun can cause power outages, radio blackouts, and GPS confusion.
The sun is constantly writhing with activity, with plasma bubbling on its surface and giant sunspots opening and closing. Sometimes, the solar surface erupts and sends a burst of plasma and electrically charged particles shooting toward Earth.
As the solar particles wash over Earth, our planet's magnetic field lines send them toward the north and south poles, where they penetrate into the upper layers of the atmosphere and interact with gas molecules to create the dancing lights of the aurora.
Bigger solar eruptions can produce beautiful auroras as far south as Pennsylvania, Iowa, and Oregon.
But a really, really big one can shut down power grids, confuse GPS, and disable radio communications.
Earth's atmosphere blocks the radiation from these solar eruptions, shielding people on the ground, but it can't stop the magnetic and electrical activity from messing with our technology.
"The risk from severe space weather is that it disrupts the technologies now vital to human life," Mike Hapgood, a space-weather consultant at the Rutherford Appleton Laboratory in the UK, told Insider via email. "This has become a big issue only in the past sixty years, say since 1960, as electricity has replaced coal as a key energy source for homes and offices."
We're in a new solar cycle, with the sun building to maximum activity in July 2025. Solar flares and space storms will probably be common over the next three years.
That's primetime for the possibility of a giant, blackout-inducing solar event.
What is a solar flare and how do they affect Earth?
A solar flare, which is a burst of radiation that accelerates charged particles away from the sun, travels at the speed of light, so by the time forecasters see it, it's already affecting Earth's ionosphere, according to NASA. That can cause radio blackouts.
Coronal mass ejections are a more violent, targeted eruption when a cloud of plasma and magnetic fields shoots out into space.
CMEs primarily affect the magnetosphere, jostling Earth's magnetic field lines in an event called a geomagnetic storm, also known as a solar storm. That's what can cause power outages.
Forecasters can issue warnings ahead of CMEs. Some CMEs reach Earth as fast as 15 hours after they're first spotted, while others can take days, according to the National Oceanic and Atmospheric Administration's Space Weather Prediction Center.
As with any disaster, however, it's wise to plan ahead so you're not rushing to stock up on supplies at the last minute.
Start now: Stock up on supplies for living without electricity
Geomagnetic storms can produce extra currents in the power grid, which interfere with transformers and can cause outages.
"I'd expect that interference to cause parts of the power grid to shut down to prevent wider damage, and the operators would need some time to restore normal operation, maybe hours, maybe a day or two," Hapgood said.
That's what happened in Quebec in 1989. An inundation of particles from the sun knocked out the region's power for about nine hours.
"I'd rate that as a once-in-a-century event in any particular location," Hapgood said, adding that any solar-storm power outage would likely be across a region of roughly 1,000 miles.
"It is important for people to have some personal resilience to loss of electricity," he added.
That means stocking up on nonperishable food, clean water, cash, battery-powered or hand-crank flashlights, blankets and warm clothes for the winter, and some means of cooking safely without electricity.
It's also a good idea to have a battery-powered or wind-up radio to get news and weather updates. But there's a chance that won't work during a solar storm, either.
Don't plan to rely on radio or GPS
Remember that solar flares, as well as CMEs, can degrade radio signals and even cause radio blackouts. Two solar storms cut off emergency radio communications for a total of 11 hours shortly after Hurricane Irma in 2017.
Geomagnetic storms also interfere with satellites and can even push them out of orbit, disrupting GPS on Earth. So it could be smart to print out directions to key spots or emergency-evacuation locations ahead of time.
You may want to avoid flying during a solar storm
Earth's atmosphere protects people on the ground by blocking the powerful radiation that comes with solar flares and CMEs. But being on a plane during a flare or solar storm can expose you to high doses of radiation, research has shown.
In some cases, you might not be able to get on a plane anyway. If your flight goes over the Arctic during a geomagnetic storm, it could be canceled or rerouted due to the risk of communication blackouts and navigation failures.
Don't ever run a generator indoors
This mistake is a common killer in the aftermath of disasters and power outages. Generators produce carbon monoxide, so experts recommend you never run them indoors or in an enclosed space like a garage, shed, or basement. These machines can fill the area with poisonous gas and kill people in just minutes.
The same goes for charcoal grills: Never use them indoors, even if the area is well-ventilated. Charcoal also produces carbon monoxide.
Being disaster-ready overall can prepare you for solar flares
Getting ready for the possibility of a major solar flare isn't that different from getting ready for any other disaster. For hurricanes, earthquakes, snow storms, pandemics, or zombie apocalypses, it's also crucial to prepare to lose power.
If you follow the basics of disaster preparedness, you'll probably be ready for a solar flare.