Science Study Confirms 481-Meter Tracy Arm Megatsunami, Second-Largest on Record

Overview

• Researchers reconstruct the tsunami that hit Tracy Arm in August 2025 as a 481-meter wave, placing it behind only Alaska’s 1958 Lituya Bay event.
• A sudden fall of about 64 million cubic meters of rock into the fjord in under a minute displaced water in the narrow channel and stripped vegetation high up the walls.
• Scientists mapped the wave height from clear trim lines where trees were ripped away and from satellite images, seismic records, field surveys, and eyewitness reports.
• Seismic data show a week of small quakes before the slide and global signals during it, raising hope for local early-warning systems if real-time monitoring expands.
• The study reports no injuries because the collapse happened around 5:30 a.m. before cruise traffic, and some operators have now paused visits as experts urge hazard mapping and safety protocols.