Greenland's 650-foot mega-tsunami lasted for nine days: What caused the wave, how scientists solved mystery

A catastrophic rockslide in a remote Greenland fjord in 2023 triggered a rare and powerful tsunami that defied expectations, not by its size alone, but by how long it endured. For relentless days, the wave ricocheted back and forth within the steep walls of Dickson Fjord, creating a rhythmic seismic pulse that echoed across the globe. Now, thanks to detailed satellite data from NASA and France’s CNES, scientists have unraveled how this ‘mega-tsunami’ unfolded and why it could be a warning sign of climate-linked instability in the Arctic.