A massive 8.8-magnitude earthquake struck Russia’s Kamchatka Peninsula on July 30, triggering tsunami warnings across at least 16 countries. The quake, one of the strongest ever recorded, hit at 11:25 a.m. local time and caused mass evacuations. “Ports near the earthquake’s epicentre were flooded,” forcing residents to flee inland.

Tsunami waves have already hit Japan, Alaska, and Hawaii. Kamchatka saw waves as high as 13 feet, while Japan’s Hokkaido recorded 2 feet and Alaska’s Aleutian Islands saw waves 1.4 feet above tide levels. Traffic in Honolulu was gridlocked as people rushed to evacuate.

Countries under warning include the US, Russia, Japan, Chile, New Zealand, Canada, China, and others. The UK’s Foreign Office urged travelers to “follow the advice of local authorities.”

Experts warn tsunamis are “a series of powerful waves over a long period,” and the danger could last for more than a day. “They slow down near shore and start to pile up,” said tsunami coordinator Dave Snider.

Although several people in Kamchatka sought medical help, no major injuries or serious damage have been reported. This earthquake is the most powerful globally since Japan’s 2011 disaster and ties as the sixth strongest ever recorded.