🌅 The Second-Tallest Tsunami on Record Hit Alaska in 2025

SOURCE

Shugar et al. (2026)

WHAT TO KNOW

• The second-tallest tsunami ever recorded struck the Tracy Arm fjord in  southeast Alaska on August 10, 2025, after a massive landslide at the toe of the South Sawyer glacier dumped 64 million cubic meters of rock into the water. Researchers at the University of Calgary in Canada found the landslide triggered a wave that reached 1,578 feet (481 meters) up the wall of the fjord, stripping the surface to bare rock as it surged through the narrow passage. Rather than dissipating, the energy from the tsunami became trapped inside the steep-sided fjord, pushing water back and forth for more than a day. For context, the Eiffel Tower is about 1,000 feet tall. Watch an animation of the tsunami.

WHY IT MATTERS

• The Tracy Arm fjord is a popular location for cruise ships, however, no vessels were caught when the tsunami hit at 5:30 am. Experts say the event is a warning about the risks of coastal rockslides triggered by glacial retreat and a reminder that climate change poses threats in myriad ways. The tsunami was just shorter than the tallest on record, measured at 1,720 feet in Lituya Bay, Alaska in 1958.

CONNECT THE DOTS

• Landslides can produce significantly taller tsunamis than earthquakes due to differences in water depth and displacement, posing a distinct hazard for environments like fjords. Alaska has experienced several tsunamis triggered by landslides in recent decades, including a 633-foot wave after a landslide near a receding glacier in the Taan fjord in 2015 and a 180-foot wave after a landslide in Kenai Fjords National Park in 2024. The 1958 tsunami in Lituya Bay was also triggered by a landslide.