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- Lituya Bay
- Episode 6
Lituya Bay: One Wave. 1,720 Feet. Survivors.Episode 61:37
The Slide That Threw Water 500 Meters High
Researchers reconstruct the enormous 1958 collapse—and encounter a geographical paradox at the mouth of the bay.
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Transcript
Water climbed 1,740 feet up the opposite wall of Gilbert Inlet.
Lituya Bay is an ice-scoured tidal inlet on Alaska’s Gulf coast.
Its basin reaches 720 feet, but the entrance sill is only 33 feet.
A magnitude 7.8 earthquake struck at 10:16 p.m.
The 1958 event triggered a massive aerial rockslide into Lituya Bay.
About 40 million cubic yards of rock plunged into the water.
Howard Ulrich had brought his seven-year-old son on the Edrie. On the Edrie, Ulrich’s anchor became hopelessly stuck.
The initial wave inside Gilbert Inlet rose at least 100 feet.
The splash reached about 1,722 feet (525 meters), stripping forests from the slope.
The gravity wave raced toward the mouth at roughly 100 miles per hour.
After about a minute of shaking, Howard Ulrich heard a roar.
In the outer bay, two of the three fishing boats were sunk.
Afterward, the wave left a sharp trimline where forests had been destroyed.
Researchers later built laboratory models to reproduce the exceptional run-up.
The models showed a huge air cavity could displace more water than rock alone.
For a moment, the catastrophe became an invisible shape beneath the spray.
Where it leaves off
Despite throwing water more than 500 meters uphill, the 1958 event did not penetrate into the ocean—so what trapped the catastrophe inside Lituya Bay?
Sources
- ALASKA STATE LIBRARYdggs.alaska.govprimary
- 60 years ago: The 1958 earthquake and Lituya Bay megatsunami | Alaska Earthquake Centerearthquake.alaska.edusecondary
- LANDSLIDE TSUNAMISnctr.pmel.noaa.govsecondary
- Interagency Technical Operations Plan fordggs.alaska.govsecondary
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