On September 16, 2023, more than 25 million cubic yards of rock and ice – enough to fill 10,000 Olympic-size pools – broke loose and plunged into Dickson Fjord.

The impact hurled up a mega-tsunami wave, reaching about 650 feet high.

The surge barreled down the two-mile corridor, bounced off the headland, and tore back again, wrecking roughly $200,000 in equipment at an empty research post on Ella Island.

Water did not calm after the first pass. Instead, it began rocking from wall to wall, a motion known as a seiche.

Computer models later showed the surface rising as much as 30 feet, then sinking the same amount in a steady rhythm that pressed on the seafloor like a giant piston.