Waves are messengers of distant storms, carrying energy across the planet
On the winter solstice of 2024, a wave nearly twenty meters tall rose in the North Pacific during tropical storm Eddie — and for the first time in the history of satellite oceanography, a spacecraft was precisely positioned to witness it. The joint NASA-CNES satellite SWOT recorded not just the wave's height, but the extraordinary journey of its energy across 24,000 kilometers of ocean, from the Pacific through Drake Passage and into the Atlantic. This moment is less about a single wall of water than about humanity's slowly expanding capacity to see what the sea has always been doing in secret — and to reckon, at last, with what we have been missing.
- A six-story wave materialized in the open Pacific during a December storm, and for once, a satellite was watching — producing one of the most significant ocean measurements since space-based monitoring began in 1991.
- The wave's energy did not die with the storm; it traveled 24,000 kilometers across multiple oceans, silently reshaping conditions for ships, coastlines, and submarine infrastructure thousands of miles from its origin.
- Researchers discovered that existing forecasting models had been systematically overestimating how much energy long-distance waves carry, exposing a quiet flaw in the tools used to protect maritime safety worldwide.
- SWOT's precise data is now being used to recalibrate those models, with the promise of sharper warnings for offshore platforms, cargo routes, and coastal communities vulnerable to the memory of distant storms.
- The deeper question — whether a warming climate is making such extreme waves more frequent — remains unanswered, but scientists now hold the kind of verified, high-resolution evidence needed to begin pursuing it seriously.
On December 21, 2024, tropical storm Eddie drove a wall of water nearly 19.7 meters high across the North Pacific — roughly the height of a six-story building. The satellite SWOT, operated jointly by NASA and France's space agency CNES, happened to be passing overhead and captured the measurement with a precision that buoys and research vessels scattered across vast ocean gaps simply cannot provide. It stands as one of the largest waves ever recorded in open water since satellite monitoring began in 1991.
What captivated researchers was not only the wave itself, but its aftermath. As Eddie weakened, the energy it had unleashed did not dissipate — it traveled. Moving south across the Pacific, through the notoriously violent Drake Passage between South America and Antarctica, and onward into the Atlantic, the wave's energy covered approximately 24,000 kilometers before its journey ended. Waves, in this sense, are planetary messengers, carrying the force of distant storms to coastlines and shipping lanes that never saw the original tempest.
The data also exposed a flaw in existing models: oceanographers had been overestimating how much energy certain long-distance waves could sustain. SWOT's measurements now offer the raw material to correct those predictions — a meaningful advance for the safety of ships, offshore platforms, and coastal communities. A wave that tall moving through a shipping lane is not a curiosity; it is a hazard.
Scientists are careful to note that this is not proof the December wave was the largest ever — only that it is the largest clearly verified by satellite. The ocean remains too vast, and extreme waves too fleeting, for any instrument to catch them all. Whether climate change is making such events more common is a question still being worked through. What is certain is that SWOT has given researchers the ability to see something that was previously invisible, and that seeing it has already begun to change what we know about how the ocean moves.
On December 21, 2024, a wall of water rose across the North Pacific. The wave reached 19.7 meters—the height of a six-story building—during tropical storm Eddie. A satellite called SWOT, operated jointly by NASA and France's space agency, was passing nearby when it recorded the measurement. The reading stands as one of the largest waves ever captured by satellite in open ocean since monitoring began in 1991.
The SWOT satellite was designed to do exactly this: to watch the world's water from above with precision that ground-based instruments cannot match. Traditional wave monitoring relies on buoys and research vessels scattered across vast stretches of ocean, leaving enormous gaps in coverage. SWOT fills those gaps. It measures not just wave height but direction, energy transport, and the subtle topography of the sea surface itself. When Eddie churned across the Pacific, SWOT happened to be in position to record what happened.
But the wave itself was only part of the story. What fascinated researchers was what came after. As Eddie weakened and moved on, the waves it had generated did not simply dissipate. They kept moving. They traveled north to south across the Pacific, passed through the Drake Passage—the notoriously rough waters between South America and Antarctica—and continued into the Atlantic. By the time the energy from that December storm had finished its journey, it had crossed approximately 24,000 kilometers of ocean. Waves, in this sense, are messengers. They carry the memory and force of distant storms across the planet, influencing coastlines and shipping lanes thousands of miles away from where they were born.
This discovery revealed something else: the forecasting models that oceanographers use to predict wave behavior were getting some things wrong. The models had been overestimating how much energy certain long-distance waves could carry. With SWOT's precise measurements, researchers now have the data to recalibrate those predictions. Better forecasts mean better warnings for ships, offshore platforms, submarine cables, and coastal communities. A wave that tall, moving through shipping lanes, is not an abstraction—it is a hazard.
Scientists have been watching ocean waves from space for more than three decades, but they emphasize that recording a wave this large does not mean larger waves have never occurred. The ocean is too vast, and storms move too quickly. Most extreme waves happen in places where no one is watching. What SWOT offers is not proof that this was the biggest wave ever, but rather the first clear, satellite-verified measurement of a wave at this scale in open water. The real achievement is the capability itself: the ability to see what was previously invisible.
The question of whether climate change is making waves like this more common remains open. Warmer oceans can fuel more energetic storms, but other factors matter too—the path a storm takes, the depth of the seafloor beneath it, the natural variability of climate systems. Researchers are still working through the data, still building the models that will help answer that question. For now, what is certain is that a satellite saw something remarkable, and that seeing it has already changed what we understand about how the ocean works.
Citas Notables
Waves function as messengers of storms, transporting energy across the ocean even when atmospheric systems do not directly reach certain coastal areas— Research team analyzing SWOT data
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter that a satellite saw this wave instead of, say, a ship's captain or a buoy?
Because ships and buoys are almost never where the biggest waves happen. The ocean is too large. A satellite can watch millions of square kilometers at once. It can be in the right place at the right moment by design, not by luck.
So this wasn't the biggest wave ever, just the biggest one we've measured?
Exactly. Bigger waves have almost certainly happened. But we have no record of them. This one we can verify, down to the centimeter. That matters for science.
The wave traveled 24,000 kilometers. How is that possible? Doesn't it just break on a beach?
Not these waves. They're not the kind that surfers ride. They're deep-water waves—they move through the ocean without losing much energy. They can circle the planet if nothing stops them.
And the forecasting models were wrong?
They were overestimating how far the energy could travel. Now that SWOT has shown what actually happens, researchers can fix those models. Better predictions mean ships get better warnings.
Is climate change making waves bigger?
That's the question everyone wants answered. Warmer water can make storms stronger, which could mean bigger waves. But it's not simple. Storm paths matter. Ocean depth matters. Natural variation matters. The data is still being analyzed.
What happens next?
More storms will come. SWOT will keep watching. Each measurement adds to the picture of how the ocean really behaves, not how we thought it behaved.