Tsunamis have inspired plenty of highly entertaining Hollywood movies, but in reality, tsunamis are extremely serious cataclysmic events. These giant waves, sometimes as much as 100 feet high, crash into land following an earthquake, volcano, or other incident that displaces a large amount of ocean water. Tsunamis arrive in a series of waves, not as a single wave as many think, and can spread out over a large area. The deadliest tsunami in modern history was the Boxing Day Tsunami on December 26, 2004, which took the lives of 230,000 people in eleven countries across Southern Asia.
The first and most important step in tsunami preparation is educating yourself on tsunami signs, warning systems and evacuation plans. If you have property along a coast, you can also take some precautions to protect it. Feel more confident about your safety when seaside by learning out how to survive a tsunami with these tsunami preparation steps.
How to Prepare for a Tsunami:
- Learn the warning signs. Be sure your entire family knows tsunami warning signs and how to evacuate.
- Plan modifications to your home. If you live within several hundred feet of the coast, you will likely need to protect your home against tsunami waters and flood waters. This is especially relevant if you are building or purchasing a new home.
- During a Tsunami, get to higher ground as quickly as possible and stay there until you are cleared to leave.
1. Know the Warning Signs
When the ocean floor suddenly moves, it displaces a large amount of ocean water which forms the giant waves of a tsunami. A jolting ocean floor is mostly caused by earthquakes, but can also be due to volcanoes, underwater landslides, or in rare cases, meteorites. Initially, the waves of the tsunami are short and move quickly over deep water, sometimes up to 500 miles an hour. They grow in height and slow down in speed as water depth decreases closer to shore. By the time they hit land, tsunamis become 10 to 100 feet tall.
Signs of a Tsunami
Before the wall of water crashes on land, the water may recede, exposing the sea floor like an extremely low tide. Other times, you may hear a roaring sound like a train. These are signs that a tsunami is just about to hit, and you need to run to higher ground.
There may be little time between the incident that causes the tsunami and the tsunami reaching shore. The famous Boxing Day Tsunami hit the first town just 20 minutes after the 9.1 earthquake that triggered it.
Areas at Greatest Risk
Tsunamis can strike anywhere, but the areas at greatest risk in the U.S. are the Pacific and Caribbean coasts. Any low-lying coastal area, like bays, lagoons, harbors, or low-lying beaches (not on a cliff) are the most vulnerable during a tsunami.
Tsunami Alert Systems
To alert people to forming tsunamis, there are a series of international, national, and local tsunami warning systems. A central one is the Pacific Tsunami Warning System, a coalition of 26 countries that maintain a network of seismic equipment and water level indicators to identify tsunamis. Some systems use text messages, while other systems have sirens along the beach.
Learn Your Tsunami Risks
Find out if you live, work, or have children who go to school in a tsunami hazard area. If so, learn the area’s evacuation plans. Create a family evacuation plan and a meeting place in case you are separated when the tsunami strikes. Plan on evacuating to ground at least 100 feet above sea level or two miles inland.
To recap, here are the key takeaways:
- Since the main cause of tsunamis are earthquakes, move away from shore if you feel or learn there’s been a tremor.
- Run to higher ground if you hear a loud roar from the ocean, or see the water draining away or rising up.
- Tsunamis can strike anywhere, but the Pacific Coast and Caribbean Islands are US regions and territories at greatest risk.
- Low-lying areas near the coastline, like bays, lagoons or harbors, are most vulnerable during a tsunami.
- Check out tsunami.gov to learn more about this warning system
- Know your area’s evacuation plans and create a family meetup plan.
TAKE THE NEXT STEP: Learn signs of tsunamis and sign up for your area’s tsunami emergency alerts.
2. Protect Your Home with Necessary Modifications
Living along the coast has the benefits of daily beach walks, breathing the ocean air, and watching marine birds and animals in their natural habitat. But if you are a property owner along the Pacific coast, there is a concern for devastating property damage during a tsunami. A big piece in learning how to prepare for a tsunami is thoroughly preparing your property in advance. Give yourself peace of mind by making these changes to your property if you live within several hundred feet of the coast or are considering building near the coast of a tsunami-prone area:
- Build flood barriers.
- Elevate your home above flood waters.
- Consult with an engineer if you are building near the coast.
Other tsunami preparedness steps include:
- Make copies of important personal, family, legal and financial documents and store them in a water-safe container or in a password-protected file.
- Purchase earthquake and flood insurance, since standard homeowner’s insurance does not cover either.
TAKE THE NEXT STEP: Contact your insurance agent to set up flood and earthquake insurance.
3. What To Do During a Tsunami
If you have learned the causes of a tsunami, are familiar with tsunami alert systems and know your evacuation plans - great job! You have already done most of the work needed to survive a tsunami.
If you are under tsunami warning, or if you detect signs of a tsunami, here’s what to do:
- If there is a tsunami warning, or you have detected the signs of a tsunami, move to higher ground immediately. If there has been an earthquake, a clear sign of a possible tsunami, wait to move until after the shaking has stopped. (Learn more about earthquake preparedness here.) You want to get to ground 100 feet above sea level or two miles inland.
- Do not leave higher ground until you are told it is safe to do so. Remember, tsunamis are a series of large waves that can last for hours.
- Stay tuned to National Oceanic and Atmospheric Association (NOAA) radio, or a local broadcast with emergency information.
TAKE THE NEXT STEP: Choose a higher ground area for your family to evacuate to, and make sure everyone in the household knows.
A little preparedness goes a long way in learning how to survive a tsunami. Knowing the warning signs, preparing your home to the best of your ability, and knowing what to do if a tsunami happens ensures optimal safety when enjoying a life near the sea.
4. Download the harbor App
The all-in-one safety and emergency app that does all the thinking for you - making it the simplest way to keep your home and family safe. Join countless families who are using harbor to quickly and easily prepare for all of life's emergencies. Get the harbor app on iOS.