In an interesting coincidence, the U.S. Department of Defense will simulate a catastrophic national power outage on Nov. 4, the same day “antifa” demonstrators are planning a purported national “day of rage” that has some on the right all worked up.



Only some people don’t think it’s such a coincidence. Infowars, for one, expressed skepticism about the timing, and as fast as you can say Grover’s Mill, a conspiracy was born.

“U.S. Electrical grid going down Nov. 4-6???” read one tweet on Oct. 29. Another panted “ANTIFA BLACK OUT NOV. 4TH PLANS CIVIL WAR.” On the Army Military Radio Auxiliary System Facebook page, one man from Columbia, Louisiana, asked: “How will this affect me? I live in the country. I know how to use oil lamps.”

OK, first, calm down, people: This is just an exercise, courtesy of the U.S. Army’s Network Enterprise Technology Command (NETCOM). No one is even actually touching the grid, except perhaps for the squirrels that routinely frolic on power lines across the country.

This is one of four exercises NETCOM will hold this year, out of the hundreds the Department of Defense runs on tabletops and in the field around the world in any given year. These games all have different storylines, depending on what the military is practicing or testing. In this case, NETCOM came up with a fictional coronal mass ejection, or solar storm, as a way to test the Army Military Radio Auxiliary System, also known as MARS. MARS, a network of amateur radio operators across the country—think guys with a ham radio in the garage—would in theory still function if a solar storm took down the entire U.S. grid system, landlines, cellphones, and the internet.

Eric Hortin, a public affairs officer at NETCOM ,confirmed that the exercise will have no effect on anyone’s phones, computers, or lights in real life. None. So, put away the oil lamps. Moreover, NETCOM came up with the scenario a year ago, and it’s likely that no one there had heard of “antifa” then. “We’ve had close to 500 calls about this just since yesterday,” Holtin said Thursday.

The faux conspiracy does highlight a more interesting question, however: Is the scenario actually feasible? Could a solar storm wipe out the entire U.S. power grid system? Or more to the point, could a manmade electromagnetic pulse (EMP) do so? The question is more than academic, given that in September, North Korean state media specifically claimed the country could generate a high-altitude electromagnetic pulse (HEMP) from a nuclear blast.

The bad news: The scenario is feasible. Solar storms, and “space weather” more broadly, are a real thing. The most famous severe geomagnetic disturbance in North America was the 1859 Carrington Event, which fried telegraph lines. More recently, a 1989 solar storm caused a nine-hour power outage in Quebec, and the National Academies of Science noted in 2008 that a “space weather Katrina” was “not inconceivable.” In other words, no one is really sure how likely a truly catastrophic solar storm is, or even what the effects would be. Indeed, the Federal Regulatory Energy Commission has adopted standards to mitigate the impacts of geomagnetic disturbances.

Then there’s the manmade threat. The North Koreans have allegedly tested six nuclear devices, claiming the most recent was a hydrogen bomb. They have tested numerous ballistic missiles, too, including an intercontinental ballistic missile, though it is not clear that it’s really a fully functional ICBM. It’s also not clear the North Koreans could actually launch a nuclear weapon anywhere, let alone over the United States, but they certainly are working on it.

Even if the North Koreans could manage it, it’s not totally clear that such an electromagnetic pulse would wipe out the entire U.S. grid and all telecommunications. The main evidence for such damage is the 1962 U.S. Starfish Prime nuclear test over the Johnston Atoll. This was a 1.4 megaton hydrogen bomb, much larger than the alleged Korean device, and it had an unexpectedly broad second-order effect, knocking out streetlights as far away as Hawaii and damaging satellites. Would it be worse in our wired world today, over a populated area, with a smaller bomb? No one knows for sure.

If the North Koreans detonate a nuclear weapon over the United States, however, they have just started World War III, and their country would soon cease to exist. (The United States does not, after all, keep all of its own nuclear weapons inside the country.) It would probably be prudent to be a little more certain of the effects of using such a weapon before courting annihilation, but far be it for me to advise the North Koreans.

That does not mean there’s nothing to worry about. The North Koreans have said they intend to test a nuclear weapon over the Pacific, for example, which seems far more probable in the near term. A test could have a range of dire consequences, including knocking out satellites. Can you imagine daily life without GPS? I’m not sure people even know how to read a paper map anymore. And there’s the rub: Regardless of what the threat is, the vulnerability is huge. We are a society utterly dependent on electricity and communications.

And nuclear weapons are not the only way to generate an EMP, either. The Department of Defense’s most recent annual report to Congress on China’s military and security developments noted that the country’s electronic warfare doctrine “emphasizes using electromagnetic spectrum weapons to suppress or to deceive enemy electronic equipment.” The United States is also developing such weapons.

These technologies are likely aimed at taking out military capabilities in a specific area, but that doesn’t mean they couldn’t also target civilian infrastructure. Indeed, past news reporting has identified a number of countries that spy on the U.S. electric grid system, and critical infrastructure is often a target in a time of war.

In other words, there are real concerns when it comes to electromagnetic pulses, but not necessarily the ones that seem to light up the conspiracy theories. Alas, poor NETCOM: They were ready for a geomagnetic storm and got a Twitter storm instead.