Tsunami warnings breakdown: Everything you need to know, how to stay safe, do's and don'ts after the 8.8 Russian earthquake

A powerful 8.8 magnitude earthquake struck off Russia’s Kamchatka Peninsula on July 29, 2025, prompting widespread tsunami warnings across the Pacific. From Japan and Hawaii to the U.S. West Coast, Chile, and Southeast Asia, millions were placed under evacuation advisories or watched with growing concern as tsunami waves began reaching coastal shores. With waves over 10 feet in some areas, the quake has raised urgent questions about safety, preparedness, and response. Understanding how tsunami alerts work and what actions to take can make the difference between life and death. Here’s a detailed breakdown of what you need to know.

What do different tsunami alerts mean?
Tsunami warning

This is the highest level of alert. It means tsunami waves are imminent or already occurring and pose a serious threat to coastal areas. Immediate evacuation to higher ground is advised. Authorities may use sirens, text alerts, and loudspeakers to issue real-time updates. Shelters may be opened, and roads redirected for evacuation. Delaying action during this stage could be fatal.

Tsunami advisory

This alert indicates that a tsunami capable of producing strong currents and dangerous waves is expected, though widespread flooding may not occur. While coastal flooding might be limited, the ocean’s behavior becomes unpredictable. Stay out of the water and off beaches, and remain alert for updates. Marinas and harbors may be especially hazardous during this time.

Tsunami watch

This means a tsunami is possible, but there isn’t yet enough data to confirm. It’s a time to prepare and monitor further alerts. Watches can be upgraded quickly as new seismic data arrives. Stay tuned to official sources and avoid dismissing the risk, even if the water seems calm.


Regional impacts of the Russian quake
Russia (Kamchatka Peninsula)
Waves between 10 to 13 feet struck the eastern coast, damaging buildings in Severo-Kurilsk. An emergency was declared, and residents were quickly moved to higher ground. Although no casualties have been reported yet, infrastructure damage is being assessed. Emergency crews are distributing food, water, and supplies to remote areas.


Japan
Up to 60 cm (2 feet) waves reached areas from Hokkaido to near Tokyo. Nearly two million people were under evacuation advisories. Railway and airport operations were temporarily suspended, and sea walls were closely monitored for breaches. The Japanese Meteorological Agency maintained constant updates through public broadcasts.

United States
Hawaii reported waves as high as 10 feet. Urgent evacuations were carried out in low-lying coastal zones. The U.S. West Coast, including California and Alaska, faced tsunami advisories. Schools and public offices closed early, and residents were urged to stay off coastal roads. The NOAA continues to monitor ocean activity across Pacific regions.

Other affected regions
Tsunami alerts extended to Chile, Peru, Mexico, Panama, Taiwan, Indonesia, and the Philippines. Some areas experienced waves up to 1 meter (3.3 feet). Coastal communities were put on standby, and several governments activated disaster response protocols. In many areas, beach tourism came to a sudden halt.


How tsunamis form and why they're dangerous
Tsunamis are typically triggered by sudden shifts in the seafloor—most often caused by undersea earthquakes, landslides, or volcanic eruptions. These geological events displace massive volumes of water, creating long, high-energy waves.

In deep water, tsunami waves can pass unnoticed; near shore, they slow down and rise dramatically. This phenomenon, known as wave shoaling, makes tsunamis especially dangerous as they appear suddenly and with immense force.

They behave like fast-moving floods, not typical ocean waves. Even small tsunamis can carry enough force to sweep away cars, homes, and people. Coastal infrastructure, including seawalls and levees, may not be sufficient against powerful surges.


How monitoring systems work
DART (Deep-ocean Assessment and Reporting of Tsunamis) buoys track sea-level changes in real time. These specialized buoys are connected to pressure sensors on the ocean floor and are part of an international network.
These buoys send information to global tsunami warning centers, helping authorities make quick decisions about alerts and evacuations. Combined with satellite data and seismic readings, they form the backbone of modern tsunami warning systems.

Alerts can be upgraded or downgraded quickly based on fresh data. Public messaging systems, from text alerts to emergency sirens, are integrated into national disaster management programs.


What to do before, during, and after a tsunami
Before a tsunami: Preparation tips

• Know whether you live or work in a tsunami risk zone. Coastal and low-lying areas are especially vulnerable. Check with local authorities or online hazard maps.
• Familiarize yourself with evacuation routes and nearest high ground. Cities often have posted signs and public information about safe locations.
• Prepare an emergency kit and communication plan. Your kit should include water, non-perishable food, medications, a flashlight, and a radio. Practice evacuation drills with your family or workplace to ensure everyone knows what to do.

During a tsunami warning

• If an earthquake strikes, drop, cover, and hold. Then evacuate as soon as it’s safe. If you’re near the coast and feel a long or strong quake, don't wait for an official warning—go to higher ground immediately.
• Move inland or to higher ground—do not wait for visual confirmation of a wave. Tsunamis may arrive within minutes and may not be visible until it's too late.
• Avoid beaches, rivers, and low-lying areas. These zones are the first to be inundated. If on a boat, move to deeper waters if advised by authorities. Marina docks are dangerous and unstable during tsunamis.

Where to take shelter

• If you can’t get inland, go to a reinforced multi-story building and climb to the top. Concrete buildings with rooftop access are the safest option in cities.
• Avoid staying in small or single-story coastal buildings. These structures are highly vulnerable to structural collapse. Seek vertical evacuation where horizontal movement isn't possible.

After a tsunami

• Wait for official "All Clear" notices—multiple waves can strike over hours. Some of the deadliest tsunami waves have occurred well after the initial event.
• Stay away from flooded areas, broken roads, and debris. Downed power lines and unstable structures pose additional risks.
• Avoid using electricity or touching wet electrical systems. Floodwater can create electrocution hazards. Report any damage to local authorities.
• Use texts or social media for communication to avoid overloading phone lines. This ensures emergency lines remain open for those in critical need.

What not to do

• Don’t go to the coast to “watch” the tsunami arrive. Curiosity can be deadly.
• Don’t assume it’s over after the first wave—later surges can be stronger.
• Don’t try to swim or wade through fast-moving water. It only takes 6 inches of water to knock an adult off their feet.
• Don’t return home until officials say it’s safe. Hidden dangers and secondary waves could be imminent.

Historical context: How this quake compares
The July 29 quake is tied as the 6th strongest ever recorded worldwide. It was stronger than the 2011 Tōhoku earthquake that devastated Japan.

The strongest recorded quake was a 9.5 magnitude event in Chile in 1960. That event triggered one of the most destructive tsunamis of the 20th century.

This quake occurred at a shallow depth (~20 km), increasing its tsunami potential. Shallow quakes shift more ocean volume and release energy closer to the surface. Scientists expect strong aftershocks, possibly up to magnitude 7.5.If you're in a tsunami-prone region, staying informed and prepared can save lives. Heed official warnings, avoid unnecessary risks, and always prioritize evacuation over belongings. Natural disasters offer little warning but plenty of opportunity to be ready—plan now, stay alert, and help others do the same.