Coastal Flood Advisory

Preparing in advance of a tsunami can save your life

By Michael Kuhne, AccuWeather staff writer

Unlike tropical storms which can often be predicted far in advance, tsunamis can strike coastlines suddenly, limiting response time for government officials, residents and beachgoers close to the earthquake's epicenter.

The 2004 Indian Ocean Tsunami is the deadliest tsunami on record. The disaster claimed nearly 230,000 lives across 15 countries and caused $14 billion in damages.

Knowing the warning signs and practicing tsunami preparedness before the waves rise offers a greater chance for survival and continued safety in the aftermath of a sudden tsunami event.

2011 Japan Tsunami U.S Navy

An SH-60F helicopter flies over the port of Sendai to deliver more than 1,500 pounds of food to survivors of an 9.0 magnitude earthquake and tsunami.

What to do before the earthquake strikes

According to Susan Buchanan, director of Public Affairs with the National Weather Service, identifying whether or not your home, school, workplace or other areas you visit are in tsunami hazard zones is the first step in preparation.

Another important step is to ensure that you have multiple ways to receive official tsunami warnings. NOAA weather radios, text messaging alert systems from local governments and mobile devices capable of receiving wireless emergency alerts are all options to getting vital information as quickly as possible.

In addition to building an emergency supply kit that includes essential items for you, your family and any family pets, creating multiple emergency plans for family communication and evacuation is also a good practice.

"If you have children in school in a tsunami hazard zone, find out the school’s plans for evacuating and keeping children safe," Buchanan said.

A solid emergency plan includes mapped out routes from home, work or other places you visit to areas of higher ground and farther inland from the coastline outside of the tsunami hazard zone.

Depending on the community, evacuation routes and assembly areas might already be established. Buchanan added that it is important to plan for routes that are accessible on foot as roads can become impassible due to damage, closures or traffic jams.

The NWS recommends residents practice walking these evacuation routes, even in darkness and in bad weather, as it will help ease the evacuation during an emergency.

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"If you are visiting the coast, find out about local tsunami safety. Your hotel or campground should have this information," Buchanan said. "You may not have a lot of time after a warning. You do not want to waste it figuring out what to do."

Buchanan recommended tourists find a way to receive local alert messages.

"Find out how to sign up for these notifications on the websites of the city or county you are visiting," she said, adding that these websites may also provide other helpful tsunami safety information.

"In a large event, it may take a while for help to arrive," she added. "If possible, people may want to store supplies at locations outside of the tsunami hazard zone [with] friends or family members. In some events, communities may be uninhabitable for extended periods of time."

Recognizing tsunami warning signs

Depending on the location, some areas may have very little time following an earthquake before the destructive wave crashes into the shoreline.

Recognizing the signs Mother Nature presents might be the only warning available to those in close proximity of the quake's epicenter.

"There may not always be time to wait for an official tsunami warning," Buchanan said. "A natural tsunami warning may your first, best or only warning that a tsunami is on its way."

Natural tsunami warnings include strong or long earthquakes, a loud roar that sounds like a train or an airplane from the ocean and unusual ocean behavior, she added.

"The ocean could look like a fast-rising flood or a wall of water. Or, it could drain away suddenly, showing the ocean floor, reefs and fish like a very low, low tide," Buchanan said.

"If you experience any of these warnings, even just one, a tsunami could be coming."

The difference between tsunami watches, advisories and warnings

The Tsunami Warning Centers base all initial tsunami messages on preliminary earthquake information such as location, depth and magnitude that is received from seismic networks.

Subsequent messages and alerts are then based on impact estimation resulting from additional seismic analysis, water-level measurements, tsunami forecast model results and historical tsunami information, according to NOAA.

Tsunami watches are issued to prompt emergency management officials and the public to prepare to take action. Watches signify that a tsunami may impact an area at a later time. Watches can be upgraded to warnings or advisories or could be canceled based on updated information and analysis following an earthquake.

Tsunami advisories are issued when a tsunami "with the potential to generate strong currents or waves dangerous to those in or very near the water is imminent, expected, or occurring." The threat can remain for several hours after the tsunami's initial arrival, but significant inundation is not expected. As with watches, advisories can be upgraded or canceled based on continued analysis.

A tsunami warning is issued when a tsunami "with the potential to generate widespread inundation is imminent, expected, or occurring." Emergency management officials may be tasked with evacuating low-lying coastal areas and re-positioning ships to deeper waters under warnings.

For more information on tsunami hazards, safety and emergency procedures, please visit NOAA's official Tsunami Warning Center website.

For more safety and preparedness tips, visit

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