Water is heavy. You don't really think about it when you're swimming in a pool or taking a bath, but a single cubic meter of water weighs about a metric ton. Now, imagine a wall of water taller than the Empire State Building slamming into a mountainside at a hundred miles per hour. That isn't a scene from a big-budget disaster movie. It actually happened in 1958. When people search for the biggest tidal wave in history, they usually find themselves looking at a remote spot in Alaska called Lituya Bay.
Technically, it wasn't a "tidal" wave. Scientists get kinda picky about that. Tsunami is the better word, or more specifically, a megatsunami. This thing was absolutely massive.
The Night the Mountain Fell
It was July 9, 1958. Southeast Alaska is a rugged place, even today, but back then it was even more isolated. Around 10:15 PM, a massive earthquake with a magnitude of 7.8 struck along the Fairweather Fault. This wasn't just a little rattle; it shook the crust so hard that it caused a massive subaerial rockfall at the head of Lituya Bay.
Basically, about 40 million cubic yards of rock—that's enough to fill a football stadium dozens of times over—let go from a height of about 3,000 feet. It fell straight into the narrow waters of Gilbert Inlet.
The impact was catastrophic.
Imagine dropping a brick into a bathtub, but the brick is a mountain and the bathtub is a T-shaped fjord. The splash was forced upward. It didn't just ripple out; it surged up the opposite shoreline with such violence that it stripped the soil and every single tree off the rock up to an elevation of 1,720 feet (524 meters).
To put that in perspective, the Eiffel Tower is only 1,083 feet tall. This wave reached heights that defy common sense.
👉 See also: Statesville NC Record and Landmark Obituaries: Finding What You Need
Survival Against All Odds
You’d think anyone in the bay would have been vaporized instantly. Most were. But Howard Ulrich and his seven-year-old son were anchored in their boat, the Edrie, when the world ended. Howard woke up to the sound of the earthquake and saw the wave coming. He later described it as a wall of water that looked like a mountain itself. He did the only thing he could: he let out the anchor chain and started the engine.
The Edrie was swept up. It rode the crest of the wave over the tops of trees that were being snapped like toothpicks. Somehow, the boat stayed upright. When the water receded, Howard and his son were still alive, floating in a bay filled with millions of splintered logs and debris.
Another couple, the Swansons on the Badger, weren't as lucky in their vessel choice but still survived a harrowing ordeal. Their boat was lifted over the spit at the entrance of the bay and dumped into the open ocean. They had to abandon ship into a small skiff as the Badger sank. Sadly, another boat in the bay, the Sunbeam, vanished completely with two people on board. They were never found.
Why Lituya Bay is a Tsunami Trap
Lituya Bay is a unique geological quirk. It’s about seven miles long and two miles wide, shaped roughly like a T. Because it’s so narrow and deep, it acts like a funnel. When that rockfall hit, the energy had nowhere to go but up and out.
Geologist Don Miller from the United States Geological Survey (USGS) arrived shortly after the event to study the "trimline." That's the clear line on the mountainside where the trees stop and the bare rock begins. It was Miller who confirmed the 1,720-foot height. It remains the highest wave ever recorded in modern history.
Interestingly, this wasn't the first time it happened there. Miller found evidence of previous giant waves in 1853, 1874, and 1936. The bay is essentially a recurring nightmare for anyone unlucky enough to be there during a seismic shift.
✨ Don't miss: St. Joseph MO Weather Forecast: What Most People Get Wrong About Northwest Missouri Winters
Comparing the Lituya Bay Giant to Other Disasters
When we talk about the biggest tidal wave in history, we have to distinguish between "run-up height" and "open-ocean height."
The 2004 Indian Ocean Tsunami was way more deadly. It killed over 230,000 people. However, its maximum height was around 100 feet. The 2011 Tōhoku tsunami in Japan reached about 130 feet. These were devastating because they hit populated coastlines and traveled miles inland. The Lituya Bay wave was a vertical monster, but it was contained within a localized area.
If a wave that size hit a city like New York or San Francisco? Game over. The energy involved in moving that much mass is hard to even calculate. We’re talking about a force that literally alters the local geography in seconds.
The Science of Megatsunamis
Most tsunamis are caused by the seafloor shifting during an earthquake, which displaces the entire column of water above it. Megatsunamis, like the one in 1958, are usually caused by massive landslides hitting the water all at once.
Researchers use sophisticated computer modeling now to understand these events. In 2019, scientists from the Georgia Institute of Technology and other institutions used 1958 data to refine how we predict landslide-generated waves. They found that the speed of the landslide is the most critical factor. The faster the "slug" of earth hits the water, the more terrifying the vertical run-up becomes.
There is a lingering fear about the Cumbre Vieja volcano on the island of La Palma. Some scientists suggest a massive chunk of that island could slide into the Atlantic, sending a megatsunami toward the East Coast of the United States. While most modern experts believe the "collapse" theory is exaggerated and that the landslide would happen in stages, the 1958 Lituya Bay event proves that nature is capable of creating "impossible" waves.
🔗 Read more: Snow This Weekend Boston: Why the Forecast Is Making Meteorologists Nervous
What Most People Get Wrong About Huge Waves
Hollywood has ruined our perception of these events. In movies, you see a curling, blue wave like something a surfer would ride. In reality, a megatsunami looks more like a churning wall of black mud, rocks, and smashed timber. It doesn't "break" like a normal wave; it just keeps coming, like the ocean decided to become a skyscraper and walk onto the land.
Also, it isn't just one wave. There are usually multiple pulses. In Lituya Bay, the initial surge was the tallest, but the water sloshed back and forth for a significant amount of time, continuing the destruction.
Real-World Preparation and Insights
If you find yourself in a coastal area and feel a massive earthquake—one that lasts more than 20 seconds or is so strong you can't stand up—you don't wait for a siren. You move.
- Height is life. In the case of Lituya Bay, you would have needed to be on a literal mountain to survive. In most coastal areas, getting at least 100 feet above sea level is the standard recommendation.
- Forget the car. Traffic jams are death traps during a tsunami. If you can walk to high ground, do it.
- Stay there. The first wave is almost never the largest or the last. People often die because they go down to the shore to see the "receding water" or to look for survivors after the first surge passes.
- Natural warnings. If the ocean suddenly disappears (drawback), it’s not a miracle; it’s a vacuum. The water is being sucked into the approaching wave. Run.
The 1958 event is a reminder that our planet is incredibly restless. We live on a thin crust floating over a hot mess of magma, and sometimes, the pieces shift. When they do, 500-meter waves are a very real, very terrifying possibility.
To better understand the risks in your own area, check the NOAA Tsunami Map or the USGS seismic hazard maps. These tools show which coastlines are most vulnerable to landslide-generated surges. If you live in a fjord-heavy area like Alaska, Norway, or British Columbia, knowing the local "trimline" history could literally save your life.