JULY 30, 2025 — Following a powerful magnitude 8.8 earthquake off the coast of Russia’s Kamchatka Peninsula, tsunami warnings were issued along Japan’s Pacific coast, prompting widespread evacuations and renewed attention to the tsunami flag.
At beaches such as Ishidahama in Toyama Prefecture and Kamogawa in Chiba Prefecture, lifeguards are trained to raise and wave the tsunami flag immediately upon the issuance of a warning.
This action is typically accompanied by sirens and verbal announcements, though authorities note that the flag often serves as the most immediate and universally understood signal to evacuate.
In Kamogawa, additional measures included the use of drones equipped with speakers to instruct surfers to leave the water and seek higher ground. Evacuation sites, such as nearby schools and designated buildings, are clearly marked, and beach-goers are encouraged to familiarize themselves with local emergency routes.
Authorities, including the Tokyo Metropolitan Police Disaster Response Division, have taken to social media to promote public awareness of the tsunami flag. Their message is clear: upon seeing the red-and-white flag, individuals should leave the water at once and move inland to safety. Even relatively small tsunami waves, measuring just 20 centimeters, can pose significant risk to human life.
The flag, characterized by a red and white checkered pattern, has become an essential part of tsunami response protocols at many of Japan’s beaches.
Originally derived from the international maritime signal flag known as the “U flag,” which indicates danger ahead, the tsunami flag was adopted in 2020 as a visual means of conveying urgent warnings to swimmers, surfers, and others in coastal areas. Its high-contrast design makes it visible from long distances and particularly effective in environments where audible alerts may be drowned out by wind, surf, or crowd noise.
