Story perspectives

Alaska landslide creates 481-meter megatsunami, warns of future risk

5/9/2026

Summary

Shugar Warns Tsunami

A landslide on August 10, 2025 in Alaska generated a megatsunami that rose 481 meters up the opposite wall.
The slide released at least 64 million cubic meters of rock into Tracy Arm, generating magnitude 5.4 seismic waves and a 36-hour seiche.
A tide gauge in Juneau, 80 miles away, recorded waves up to 36 centimeters.
Geomorphologist Dan Shugar of the University of Calgary linked the collapse to glacier retreat and warned that rising microseismic activity could signal future events.

Summary

Scientists Propose Warning

Scientists say a landslide-triggered tsunami warning system could give vessels up to ten minutes notice.
Building the system would require coordination among state agencies, NOAA’s tsunami program and the Alaska Earthquake Center.
After the August 2025 slide, several cruise lines announced they will avoid Tracy Arm, cutting tourist traffic.
Authors propose an “orange” alert based on rising seismic tremor that could be issued a day before a collapse if monitoring existed.

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Shugar Warns Tsunami

A landslide on August 10, 2025 in Alaska generated a megatsunami that rose 481 meters up the opposite wall.
The slide released at least 64 million cubic meters of rock into Tracy Arm, generating magnitude 5.4 seismic waves and a 36-hour seiche.
A tide gauge in Juneau, 80 miles away, recorded waves up to 36 centimeters.
Geomorphologist Dan Shugar of the University of Calgary linked the collapse to glacier retreat and warned that rising microseismic activity could signal future events.

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