Tsunamis are a series of enormous waves that are caused by a natural or man-made disaster. The majority of tsunamis are triggered by a large earthquake or volcanic eruption that occurs underwater or near coastal areas. They can also be generated by explosions or meteors.
When preparing for a tsunami, it’s important to prepare for the other natural disasters that have the potential to cause them. For example, if you live in San Diego or Los Angeles, you should already be expectant of an earthquake. A significant quake can lead to a coastal tsunami, so if you’re anywhere near the beach you should be preparing for both disasters.
How do you prepare for a tsunami?
In order to prepare for a tsunami, you should know your risk and have an evacuation plan with routes memorized. Get an evacuation (or bug-out) kit with all the supplies to last you at least 72 hours. Keep it in your car for easy transport but make sure it’s not too heavy in case the roads are blocked and evacuating by foot is your only option.
Make an emergency and reunification plan which includes ways to get in touch with your family members after the disaster has ocurred.
In this article, we’ll be discussing the preparedness process in great detail so that you can feel ready if you’re ever in a high-risk area during a tsunami warning.
[This is a long article about becoming prepared for a tsunami.The links in the Table of Contents may help you to navigate through the page. If you don't have much time and want to dive right into the meat of this article, please click here. And don’t forget to grab your free checklist at the end!]
- Over history, 70% of confirmed tsunamis occurred in the Pacific Ocean and 81% were caused by earthquakes.
- The deadliest tsunami in recorded history occurred on December 26, 2004, in the Indian Ocean. The cause was an underwater 9.1 magnitude earthquake near Sumatra, Indonesia. This disaster claimed the lives of more than 230,000 people throughout 15 countries.
- The costliest tsunami (part of a combination of disasters) is attributed to the Japanese earthquake and tsunami that occurred on March 11, 2011. The direct cost of the disaster, according to the Japanese government, was roughly $199 billion dollars. The economic cost, however, is estimated to reach $235 billion dollars, according to the World Bank.
- The highest tsunami is believed to be the one that occurred in Lituya Bay, Alaska on July 9, 1958. An earthquake caused rockfalls in the area, one of which fell about 3,000 feet into the Bay and resulted in a tsunami that destroyed everything along its path located at or below 1,720 feet. The bay itself is at sea level, so imagine the size and strength of the waves to level the slopes.
- The worst tsunami to ever hit the US Pacific Coast occurred on Good Friday (ironic?) which was March 27, 1964. It happened after a massive earthquake struck Anchorage, Alaska.
- The tsunami capital of the United States is Crescent City, CA, a city just south of the Oregon border.
Tsunami terms you should know
Tsunami: The word tsunami literally means “harbor wave.” A tsunami is a series of massive waves that happen after a significant displacement in the Earth. Volcanoes and earthquakes are the largest culprits— typically the ones that occur underwater and in coastal areas. They can also be caused by meteors crashing into the ocean, as well as massive landslides, rockslides, icebergs, and even underwater nuclear explosions. The average height of a tsunami wave is 33 feet (10 meters) but there are records of tsunamis having produced 100 foot (30 meters) waves, so anything is possible.
Tidal wave: A tidal wave is a huge wave that is caused by the gravitational interactions between the moon, sun, and earth. The terms ‘tsunami’ and ‘tidal wave’ are oftentimes used interchangeably but they shouldn’t be. One is caused by gravitational forces, while the other is caused by an underwater or coastal displacement of the Earth.
Tsunami watch: A tsunami watch is issued by the National Tsunami Warning Center (NTWC) or the Pacific Tsunami Warning Center (PTWC). These organizations are run by the National Weather Service and each of them is responsible for monitoring earthquakes and volcanic activity below the sea in their respective regions. A tsunami watch means that there is a probability of a tsunami reaching land, but no guarantee. If you live in a coastal area and receive a tsunami watch alert, the first step should be to gather your family and review your evacuation plans. Stay tuned to the local radio for updates and instructions from the local government.
Tsunami advisory: A tsunami advisory is issued when a tsunami is inevitable or approaching a specific region. In other words, the tsunami risk is high but hasn't yet occurred. If you receive a tsunami advisory alert, you should begin executing your evacuation plans. Tsunami waves can cause tidal surges with enough strength to sweep away cars, boats, and anything along their path. They cause mass flooding near coastal regions and travel quickly. Do not attempt to watch a distant tsunami from home. Leave coastal beaches. Move inland and wait there until the threat has passed.
Tsunami warning: A tsunami warning is an escalated version of an advisory. This official warning means that a tsunami is definitely expected in a specific area. Evacuations must occur immediately. Stay away from the beach and low-lying areas. A warning may last for hours after the initial tsunami waves have made landfall, so don’t return home until local authorities say it’s safe to do so.
Current tsunami map
I couldn’t find a real-time tsunami map — I’m not sure if such a thing exists — but I did find a few cool resources instead.
The NOAA National Centers for Environmental Information has a fun interactive map where you can see previous tsunami events and significant volcanoes and earthquakes. This site can help people identify the hazards for their local area. There’s a drop-down menu where you can select a significant tsunami event from the past and it provides you with additional information about where it took place and which places were affected.
Another good resource is this global and regional hazard map, provided for by the International Tsunami Information Center. The map includes significant earthquakes, volcanoes, and tsunami hazard locations. They also have historical maps showing a record of the effects caused by tsunamis in different parts of the world.
The Pacific Network Seismic Network has hazard maps as well. They’re a bit difficult to understand but might give you an idea of what your area can expect.
Finally, if you live in a coastal state in the US, you’re going to love the National Tsunami Hazard Mitigation Program’s interactive map of the United States. Click on any blue state and it will give you the option to get inundation maps, evacuation routes, and in some cases apps with lots of safety information. There are a few states where evacuation maps are not available yet. If your state is one of those, contact your city’s Emergency Management Department to get more information. Another option is to Google your city and state’s name followed by “Tsunami evacuation routes.”
If you’re a resident of California, you may benefit by visiting the California Department of Conservation website where they also offer interactive tsunami inundation maps by county.
If you’re a resident of Oregon or Washington state, you’ll want to download the interactive NVS Tsunami Evacuation Zones map. It lets you know when a watch, warning, or advisory is in effect, as well as high and low-risk areas.
For Hawaii and Guam residents, the Tsunami Aware website has an interactive map of high-risk areas, as well as safe places to evacuate.
What to expect during a tsunami
Tsunamis are scary and dangerous. To put your mind at ease, we gathered a list of the most common tsunami questions and answered them for you here.
Mitigation of tsunamis
Tsunami mitigation is important because it can help reduce or even prevent tsunami deaths. When you know what to look out for and what to do in such a scenario, you will be able to get to safety much faster. The following tips are my suggestions on the best ways to prepare for a tsunami.
- Know your risk. If you live in a coastal area or low-lying area somewhere near the beach, you’re probably in a high-risk zone. Learn the warning systems used in your city and what they mean. The Tsunami Zone is a website that can help you narrow down information based on your city and local tsunami hazard zones.
- Learn the warning signs of a tsunami. Don’t rely on warning systems because sometimes the tsunami arrives before a warning can reach the public. Know what an approaching tsunami looks like, especially if you live in a tsunami hazard area. (Remember we already described that? If you forgot, click here for a reminder.)
- Be prepared for other disasters— these typically occur before a tsunami. Tsunamis can be triggered by several natural disasters, including major earthquakes, volcanoes, and landslides. Learn how to prepare for each of those if your area is at risk.
- Retrofit your home. If you live near coastal waters, have an inspector or contractor check your house for vulnerabilities and ways to improve the strength of the infrastructure. If you’re able to elevate the home above the projected rush of water, you might be able to save your home from flood waters. This could be costly but may be worth the investment.
- Have an evacuation plan. This is an important step for your survival. If you don’t know which places are safe to go in the event of a tsunami, then you’ll be running like a chicken with its head cut off. Identify and map out an escape route to at least one tsunami safe area near each of the places you frequent the most, such as your home, work office, your kid’s school, the gym, and the grocery store. Become familiar with getting to an evacuation zone using side streets since main roads and highways could be congested. Do not rely on your map App to get you to safety during a tsunami. If your children’s school is located in a high-risk area, ask the school what their emergency evacuation plan looks like.
- Make a family plan. Imagine being at the beach with your family. Your spouse is with one of your kids swimming in the ocean while you’re with your other child building sandcastles. Suddenly the ocean waters recede and a series of waves begin to form on the horizon. You immediately recognize what’s happening. At a moment’s notice, people are running around— it’s chaos. You pick up your child and start running inland, while frequently glancing towards the ocean for signs of your husband and your other child. You run to a place of safety, and as you start to lose the adrenaline, your mind begins to panic. Where are your husband and child? Did they get to safety? Situations like these are why we emphasize making a family emergency plan. In this plan, you should determine how you plan to get in touch with each other if you become lost during an emergency. Remember to include a reliable point-of-contact in a different state or city that everyone in the family can call to tell them they’re safe— this person can serve as the main contact to help reunite the family. Your family emergency plan should also include a reunification plan. This doesn’t only come in handy during an emergency, but anywhere you go. For instance, if you’re at Disneyland and one of your children wanders away, you need to plan ahead of time a reunification location in case someone becomes lost. Same with all types of emergencies, but especially a tsunami. If your kids are at school during the disaster, who will pick them up and bring them home? All those details need to be sorted out long before an emergency. For information on building a communication and reunification plan, check out this page. Include your children in the planning process and practice it so they know exactly what to do in case an emergency occurs.
- Build your emergency kit. If you live in a high-risk area and are at home during a tsunami warning alert, your best bet is to keep an evacuation backpack ready to go for every member of your household. This should include the minimum supplies needed to survive for 72 hours without assistance, as well as items of personal need that you or your loved ones cannot live without during an emergency situation— such as prescription medication or diapers. Include your pets in the preparedness process as well. Build them a kit with enough water, food, and a few comfort items. Your disaster kit should also include a binder with your important documents (more info on that here!) If you’re unable to carry your backpack, either because it’s too heavy or you have pre-existing injuries that prevent you from lifting heavy things, consider attaching your backpack to a dolly cart with wheels.
- Take a CPR and first aid class. By learning basic first aid and CPR you are empowering yourself to save someone else’s life— it could be your children’s life you save! Injuries are high amongst tsunami victims, and the mass destruction oftentimes makes it difficult for medical personnel to reach those in need right away. If you’re in the midst of a tsunami and you survive it, you immediately become a first responder because you’re already on the scene. Knowing how to splint an arm or how to perform CPR are invaluable skills for such a time as that.
- Get fit. I know this may sound like a silly tip — I hope it doesn’t offend anyone because that’s not my intent by any means. But hear me out. In order to survive a tsunami, you must be able to get yourself to safety—physically speaking. Outrunning a tsunami wave is impossible, but running to higher ground might not be. Whatever physical level you are at today, wake up tomorrow and do 1% better. The next day, improve another 1%, and so on. Before I started jogging, I walked at a fast pace for weeks and worked my way up. You don’t have to run a marathon but get comfortable moving quickly.
- Think about insurance. Homeowners' policies and renter’s insurance does not include tsunami damage. You may be able to get tsunami insurance through the National Flood Insurance Program by the Federal Emergency Management Agency (FEMA). FEMA’s website has more information on this insurance program and how you can obtain it. You can also contact an insurance company you trust and speak with an insurance agent directly.
Tsunami safety tips
What to do before a tsunami:
- Anytime you’re at the beach, you should be on alert for a tsunami. You just never know if you’re going to be in the wrong place at the wrong time. It’s best to be prepared so you can act out of knowledge rather than react out of fear which puts your life in even more danger.
- If you’re in a coastal or low-lying area and you feel a local earthquake, or learn that an undersea earthquake has occurred nearby, move to higher ground immediately. You may have very little time to get to safety, so move quickly. Do not wait for an official tsunami warning to take action.
- If you’re within a tsunami hazard zone, such as the beach, and the waters recede dramatically within a few seconds or you notice an unusually low tide, that’s another warning sign to get to high ground. The large ocean waves that come after this can be detrimental.
What to do in or during a tsunami:
- RUN! Get to higher ground immediately. Find a place that is 100 feet above sea level or drive 10 or more miles inland. If your only available option is to climb a few stories of a tall concrete building, then go for it. Worst case scenario, if you can’t find a safe place, grab something sturdy and hold on for dear life— this should be your last resort option.
- The first wave is typically NOT the largest. Expect more waves to follow for at least a day. They’ll eventually diminish in magnitude but don’t return to coastal or low-lying areas until local officials say the threat is over.
- Stay tuned to the local radio or television station for important updates and the latest information regarding evacuation orders in coastal communities.
What to do after a tsunami:
- Do not walk in flooded areas. Not only can floodwaters be contaminated, but they may have strong currents that can sweep you away.
- Do not walk near downed power lines. They may be live wires. It’s better to call the electric company to come out and inspect them. If you’re able to stay and wait for them to arrive, you can warn other passerby’s to stay away too.
- If your home or property has been damaged, take photos of the damage prior to moving or removing items. These photos may benefit you for insurance purposes.
- If your home is destroyed or not safe to stay in, find a local evacuation shelter for the time being.
- Do not drink water from the tap. Due to flooding, the city water may no longer be potable. Make sure to set up a water purification system at home to filter all your water through before consumption.
Tsunami emergency kit must-haves
It’s always wise to build an emergency kit for a disaster. A tsunami can occur while you’re at home, at work, at the beach, or even on vacation. Wherever you are, you should strive to keep important items with you at all times, whether it’s having an evacuation kit at home and another one in your car or at work. If you’re planning for a tsunami, it’s likely that you’ll be preparing for another disaster as well, so combine the supplies recommended for each disaster and create a comprehensive kit.
These suggestions can help you survive the first 72 hours after a tsunami hits, and hopefully, help you begin the recovery process faster if anything was damaged or destroyed.
- NOAA radio & batteries: Having a NOAA weather radio is critical because they’re usually the first to send out tsunami alerts. You should download the NOAA Weather app so you can receive the alerts on your phone as well. Keep in mind that a tsunami can occur during the night while you’re sleeping, so make sure the notifications can be heard any time of the day.
- A survival kit: This is basically your evacuation kit. It should include the minimum items to help you during the first 72 hours without assistance. Put together one kit per person in your household. Include items of personal need, such as a change of clothes, prescription medication, feminine products, diapers, and any other items that are vital yet unique to each family member. Don’t forget to include your pets in your planning and evacuation process! These are some pet survival kit solutions.
- A car emergency kit: On top of the survival kit, I recommend having a car emergency kit. I would consider this a miniature version of your home survival/evacuation kit. You may want to include several items of personal need as well, but at least have the minimum basics in case you can’t make it home in time to grab your survival kit. Your car kit should at least include one change of clothes, water, food or snacks, and first aid supplies.
- A comprehensive first aid kit: When I think of a tsunami, I think of widespread injuries. Many people have been swept away amongst the debris. The survivors oftentimes end up with severe injuries that could be life-threatening if they’re not taken care of quickly. If you’re lucky to survive with few injuries, you can become a good samaritan and help treat other people’s wounds until medical professionals arrive. Something simple like applying a bandaid doesn’t take skills but learning about splints, tourniquets, and other procedures does require training. I highly recommend getting trained in basic first and CPR if you want to be fully prepared for a tsunami. A kit is essential but having the knowledge to use the items inside the kit is even more crucial.
- Headlamp with batteries: I recommend having a headlamp but a flashlight will do just fine. A headlamp makes life a little more simple because it frees up both of your hands to do other things. Remember to include plenty of backup batteries.
- Potable water and a purification method: Drinking water is a high priority item for your emergency kit. Since flooding is likely to occur, you can expect the city water to be contaminated. You can stockpile cases of water bottles or store your water in tanks.
- Long-term food storage: Even if your home survives the tsunami, you should expect widespread damage across the coastal region of your city. You should expect delays in the delivery of food and other supplies to your city, as roads may be blocked and prevent relief from coming in. Keep a supply of long-term food stored in your house for such occurrences. These food kits are ideal because it gives you the peace of mind of not having to rotate your food in 20 years. Once reconstituted (with water), these meals will provide nutrition to your family. Rest assured that they’re made with high-quality non-GMO ingredients. A safe way to cook and prepare your food is with a stove and fuel kit like this one— it’s safe to use indoors because the fuel does not release toxic fumes. Win-win!
- Snacks: Include long-term and high-energy snacks like granola bars and nuts in your survival kit. Keep an eye on expiration dates and rotate as necessary. For a complete list of long-lasting snacks and food items, look here.
- Sanitation and hygiene kit: One of the priorities after a tsunami is maintaining your health and avoiding disease. Have disposable plates, cups, and utensils for eating meals and large trash bags to throw everything away in. Also, get a complete toilet kit for safe human waste disposal.
- Important documents: No matter which disaster you’re preparing for, you must keep copies of all your valuable documents. Keep these documents stored in a waterproof container in a safe location of your home alongside your survival kit. You should store a backup copy of each of your documents on a cloud-based server, such as iCloud or Google Drive, and remember to make those files password-protected. Digital copies are necessary if you’re not home to grab the printed version— it’s the next best thing. Learn which documents you should save copies of here.
Print the tsunami supplies checklist and safety tips below. Keep this information in your emergency kit so it's handy when you need it the most.
Destructive tsunamis can be generated by an underwater disturbance on the ocean floor, whether it be from a volcano or a strong earthquake.
Although such events are more common underwater, on occasion an above-ground earthquake, landslide, or volcano can cause a tsunami if it’s close enough to the shore. It’s a good idea to prepare for those disasters also if you live in areas prone to any of those disasters.
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Ten Years Later: Remembering the Deadliest Tsunami in Recorded History — AccuWeather
Japan Earthquake & Tsunami of 2011: Facts and Information — Live Science
California Town Still Scarred by 1964 Tsunami — NPR
Tsunami City, USA — Slate
World’s Tallest Tsunami — Geology
How are tsunami early earnings issued? — American Geosciences Institute
Global and Regional Hazard Maps — International Tsunami Information Center
Tsunami Message Definitions - National Oceanic and Atmospheric Administration/ National Weather Service