What to do during a tsunami alert: Understanding warnings, watches, and more

When a tsunami threatens Hawai‘i, knowing what each alert means can save lives. The state relies on a four-level warning system to inform the public of potential danger: tsunami watch, warning, advisory, and information statement. Each carries a specific meaning, and knowing how to respond at each stage is critical.

There are four types of tsunami alerts issued by the Pacific Tsunami Warning Center, National Weather Service, and the Hawai‘i Emergency Management Agency. Each alert signals a different level of threat and requires different action from the public. Officials are urging residents and visitors to learn the distinctions, especially in light of the recent magnitude 8.7 earthquake off Russia’s Kamchatka Peninsula, which prompted real-time watches and warnings across the Pacific.

Tsunami warning: Evacuate immediately

A tsunami warning is the highest level of alert. It means a tsunami is either already occurring or is expected to strike the coastline imminently. These warnings are usually issued following powerful undersea earthquakes, typically magnitude 7.5 or higher, or when tsunami waves are confirmed on deep-ocean sensors.

“When a tsunami warning is issued, evacuate all coastal and low-lying areas right away,” officials said. “You will hear sirens for three minutes in affected areas.”

People are advised to move to higher ground and remain there until county officials issue the “all clear.” Sirens, TV and radio interruptions, NOAA Weather Radio, mobile alerts, and official social media channels are used to disseminate warnings.

Tsunami watch: stay alert, prepare

A tsunami watch means a tsunami is possible, but confirmation is pending. These are typically issued after distant seismic events elsewhere in the Pacific.

“This is your time to prepare,” officials said. Residents should review evacuation routes, pack emergency kits, and closely monitor updates. No evacuation is required unless the watch is upgraded to a warning.

Tsunami advisory: Dangerous currents expected

A tsunami advisory is issued when waves and strong currents are expected along the coast, though widespread flooding is not anticipated. The ocean is still dangerous under these conditions.

People should stay off beaches and out of the water. Small boats should be secured, and larger vessels may be ordered out to sea to avoid damage in shallow waters.

Tsunami information statement: No threat

A tsunami information statement means there is no threat to Hawai‘i. It is used to keep the public informed following an earthquake or other offshore event. No action is needed, but officials still encourage the public to stay alert.

Know Your Evacuation Zone

Sirens are tested monthly in Hawai‘i at 11:45 a.m. on the first business day to ensure readiness. Officials strongly advise residents to know whether they live in a tsunami evacuation zone and to develop a family plan.

“If you feel strong shaking near the coast, don’t wait for an alert. Evacuate immediately,” officials warned. “Tsunamis generated by nearby earthquakes can arrive within minutes.”