The EMP Threat Is Real, and Most People Have Never Heard of It

The night the streetlights died on Oahu, nobody on the island knew why. It was July 9, 1962. A few seconds earlier, the United States had detonated a 1.4 megaton warhead 250 miles above the Pacific, near Johnston Island, roughly 900 miles away. The test was called Starfish Prime. People in Honolulu felt nothing, heard nothing. Then about 300 streetlights went dark, burglar alarms started screaming for no reason, and a telephone company microwave link failed, cutting calls between Kauai and the other islands. The sky over the Pacific glowed for minutes in colors people would describe for the rest of their lives.

That happened. It’s in the record. And most people have never heard of it.

I spent 22 years researching the novel that grew out of facts like this one, and I kept running into the same reaction. Smart, well-read people would hear the phrase “electromagnetic pulse” and assume I was describing something from a comic book. I get it. The truth sounds like fiction. But the science is real, the test was real, and a federal commission spent years telling Congress this is a problem we have not solved. So let me walk through what I found, plainly, and you can decide for yourself.

What an EMP actually is, minus the hand-waving

I’m a chemist by training, Georgia Tech, so I’ll keep this honest and skip the mystical stuff. A high-altitude electromagnetic pulse, the kind that matters here, is what you get when a nuclear weapon detonates well above the atmosphere, tens or hundreds of miles up. The explosion itself doesn’t reach the ground. The blast, the heat, the crater you picture when you think “nuclear,” none of that touches you.

What reaches you is a burst of electromagnetic energy.

When the weapon goes off, it floods the upper atmosphere with gamma rays. Those rays slam into air molecules and knock electrons loose, and those electrons get whipped around by the Earth’s own magnetic field. The result is an intense electromagnetic wave that sweeps down over an enormous footprint. Physicists break it into phases, a fast early spike and slower components that follow, and each one stresses different equipment in different ways. You can read the technical breakdown on the nuclear electromagnetic pulse page if you want the full taxonomy.

Here’s the part that matters. The wave couples into anything that conducts: power lines, phone lines, antennas, the long metal runs that thread through every modern building. Long conductors act like accidental antennas. They gather the energy and dump it into whatever’s connected. In 1962 that meant streetlights and a microwave relay. Today it means a great deal more.

Why Starfish Prime is the fact I keep coming back to

Detonate a weapon high enough and the footprint is continental, not local.

The thing about Starfish Prime is that the EMP damage in Hawaii was, by the standards of what the physics allows, mild. The weapon wasn’t optimized to maximize the pulse. The detonation was 900 miles from Honolulu, not directly overhead. The grid in 1962 was simple, rugged, mostly mechanical, with very little of the delicate solid-state electronics we now depend on for everything. And it still knocked out streetlights and alarms and a phone link across that distance. You can read the Hawaii effects on the Starfish Prime record and a good retelling of the night at RealClearScience.

The pulse also damaged satellites in orbit, including Telstar 1, the satellite that had just made the first live television broadcast across the Atlantic. Decades later, physicists were still modeling exactly what the pulse did, because the effects came out larger than the scientists of the day had predicted. The American Physical Society revisited the test sixty years on and that’s the line that stuck with me. The experts in 1962 underestimated it. They were surprised by their own bomb.

I find that more sobering than any worst-case scenario. Not the doom. The surprise.

What the people who studied this told Congress

This isn’t a fringe theory I dug out of a forum. The United States convened a formal body, the Commission to Assess the Threat to the United States from Electromagnetic Pulse Attack, and it reported to Congress over a span of years. Its members were serious people: weapons physicists, defense scientists, engineers who’d spent careers on exactly this question.

Their conclusion was not subtle.

A single nuclear weapon detonated at the right altitude, on the order of a few hundred kilometers up, could put an EMP field over the entire continental United States. One weapon. The Commission described the threat to the grid and to the infrastructure stacked on top of it, water, food, communications, transportation, as something approaching existential, because all of those systems now lean on the electric grid and on electronics, and our grid was never built to shrug off a continent-wide electromagnetic insult.

I want to be careful here, because this subject attracts a lot of hysteria and I have no interest in adding to it. Some of the most alarming numbers that get thrown around in the popular press, casualty projections and so on, are debated, and reasonable experts disagree about magnitude and likelihood. I’m not going to hand you a fake statistic to make a point. What I’ll stand behind is narrower and harder to argue with: the physics is real, the 1962 test demonstrated it, and a federal commission of qualified people concluded our grid is genuinely vulnerable and recommended we do something about it. That’s not a prophecy. It’s an engineering assessment.

Why this became the spine of the book

A story needs a clock. Something has to be ticking.

When I started The Tempest Toss, Book 1 of the John Hunter series, I didn’t want the threat to be magic or a hand-wave or some made-up super-weapon. I wanted it to be the kind of thing a reader could look up afterward and find sitting right there in the public record, exactly as I’d described it. The EMP threat gave me that. It’s grounded in real physics and real Cold War history, including the testing programs that produced Starfish Prime, and during those 22 years I corresponded with people who’d lived inside that world, people who served, and at one point even a former KGB general. I once wrote to Tom Clancy, too, because if you’re going to chase this kind of accuracy you might as well learn from the man who set the bar.

Getting the science right wasn’t decoration. It was the whole point, and I’ve written separately about why I refused to fudge the physics and about what a novel can say that the official record can’t.

If you want the human version of all this, the version with a pulse and a countdown and people trying to stop the worst from happening, that’s the novel, coming Fall 2026. If you’d rather know who’s behind it and why a chemist spent two decades on a thriller, that story’s here.

The streetlights on Oahu went dark in 1962. We’ve had sixty years to think about what that meant. I’d argue we still haven’t thought about it nearly enough.