Landslide triggers local tsunami in Southeast Alaska

A local tsunami up to 15 feet high was reported in Southeast Alaska on Sunday following a possible landslide, according to the Alaska Earthquake Center.

“We received reports this morning from the Endicott Arm area of Southeast Alaska of a local tsunami that rolled through the area just after 5:30 AM.,” the center said in a social media post. “Seismic signals large enough to be seen widely across southern Alaska confirm a significant landslide in the region at about same time.”

“All evidence suggests that this set of reported 10-15-foot high waves was set in motion by a landslide of several tens of millions of cubic meters of rock striking the water,” the agency said. Officials are working to confirm the exact location of the landslide.

Kayaker Sasha Calvey said she and two others were camping on Harbour Island in Tracy Arm Inlet, a fjord about 45 miles south of Juneau, when a landslide or iceberg caused a tidal surge that swept away half of their gear, including one boat, personal items, and cooking equipment.

Calvey said their gear had been stored about 25 feet above the high tide line, but the water reached it and came within an inch of sweeping away their tent. She added that they placed a radio distress call that was picked up by a boat, which transported them to Juneau.

Landslide-generated tsunamis occur when a large mass of rock, soil, or ice suddenly falls into a body of water, displacing it and creating powerful waves. Unlike tsunamis caused by undersea earthquakes, these events are often more localized but can still cause significant damage in nearby areas.

In some cases, landslide-generated tsunamis can reach extreme heights, such as the 1958 Lituya Bay tsunami in Alaska, which was triggered by a massive landslide and produced a wave measuring more than 1,700 feet.

The Alaska Earthquake Center said it is working with other agencies to determine the full sequence of events. No damage or injuries have been reported.