The Forgotten Lituya Bay Mega-Tsunami of 1958
In 1958, a remote Alaskan bay experienced the tallest tsunami ever recorded, towering over any wave in human history.
On July 9, 1958, in the deep wilderness of southeast Alaska, a seismic event occurred that would leave a mark on geological history—but remains largely unknown outside scientific circles. Lituya Bay, a narrow inlet surrounded by steep mountains and thick forests, was the site of the tallest tsunami ever recorded, a wave that reached an astonishing height of 1,720 feet—taller than the Empire State Building.
The series of events began just before 10:16 p.m., when a magnitude 7.8 earthquake struck the Fairweather Fault, which runs just off the bay’s edge. The violent tremor shook loosened earth along the slopes bordering Lituya Bay. Then came the catastrophic trigger: approximately 40 million cubic yards of rock and glacier from the steep hillside suddenly plummeted into the narrow tip of the bay with the force of a bomb, displacing a colossal volume of water.
The result was a wave that simply defies typical descriptions of tsunamis. Unlike the ocean-wide surges commonly associated with the word, this was a “megatsunami”—an extreme local phenomenon produced by the sheer scale of the landslide. The wave shot across the inlet at more than 100 miles per hour, scraping the land bare as high as 1,720 feet. Ancient trees were scoured from the mountainsides, rocks were stripped clean, and the landscape was forever changed.
The sudden wall of water continued down the fjord, snapping forests like matchsticks and thundering out to sea. Incredibly, there were a few eyewitnesses. A handful of fishing boats were anchored in the bay’s waters that night. Bill and Vivian Swanson, on their boat at the other end of the bay, described seeing the entire skyline “filled with a huge wall of water.” Their boat was lifted up and carried over the trees before returning to the water in one piece. Two other people, unfortunately, lost their lives.
The size of the wave at Lituya Bay is almost unfathomable even today. Most tsunamis caused by undersea earthquakes are measured in feet or meters; this one, in scale, was nearly twice the height of the Washington Monument. Yet, because this feat of nature occurred in a sparsely populated and remote wilderness, its story is overshadowed by other disasters despite its momentous significance for geologists. The area still bears silent evidence: a wedge of denuded rock and soil still dazzles new visitors, a reminder of that summer night in 1958.
Scientists have since studied Lituya Bay not only to understand the event itself, but to help assess the future threat of similar landslide-induced tsunamis—rare, but potentially catastrophic in steep coastal areas. The Lituya Bay wave also serves as a warning: nature sometimes produces forces and phenomena so extreme that they reshape what we believe is possible.
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