Tsunamis are some of the most sudden and dangerous disasters that can occur along any coastal area. A titanic mass of water pushed by the waves sweeps inland, knocking down or dragging along anything and anyone in its path.
Being overtaken by a tsunami is to be crushed by a swirling mass of debris and, assuming that doesn’t get you, you’ll be drowned.
Tsunamis can occur anywhere the land meets the oceans, and they are especially dangerous for popular tourist destinations since people will be thronging along the beaches and businesses close to the water.
Despite their unstoppable nature, tsunamis can be survived with a combination of quick thinking, preparation and a good plan. In this article, we’ll tell you how to prepare for and survive a tsunami.
Table of Contents
What Are We Dealing With?
Contrary to popular depiction, tsunamis are not the stereotypical giant, curlicue-shaped waves that you might see surfers enjoying along beaches all over the world.
In reality a tsunami is actually a series of waves created by the displacement of a large amount of water somewhere in the ocean or body of water at large.
This displacement is most often caused by undersea earthquakes, subnautical landslides, volcanic eruptions, and even asteroid or meteorite impacts.
All can create terrible tsunamis. Humans have also caused tsunamis all by themselves, typically through the detonation of massive underwater explosions, often by a nuclear warhead.
Since tsunamis are not created by typical wave mechanics like the gravitational pull of the moon, the wind, and the tide itself, they do not appear as typical waves.
A tsunami will most often appear as a rapidly rising tide, and nothing else. It simply goes, up, up, up, and clear on to land.
Due to this simple observation, tsunamis are casually called tidal waves in America and elsewhere, but this is not entirely accurate since the usual tidal mechanics have nothing to do with a tsunami.
Since tsunamis are a series of waves, and not a singular wave, they will strike the shore in succession within an interval of anywhere from minutes to hours between impacts.
So they strictly affect coastal areas, their reach inland is surprisingly long, in some cases several miles and their destructive potential is enormous. As the mass of charging water hits the beach and shore beyond, it often ramps up, gaining height.
It is these titanic quantities of moving water being driven at speed, often times in excess of 25 miles per hour, which generates such deadly force and creates destruction. In the aftermath, survivors are left to deal with all the varied effects of a major flood.
Where Do Tsunamis Occur?
Strictly speaking, tsunamis can occur anywhere there’s a large enough body of water to have a significant fraction of its mass displaced someway, somehow. Nominally, tsunamis are most common in the Pacific Ocean, but do occur fairly regularly in the Atlantic and in the Caribbean.
Historically, Southeast Asian countries, in particular Japan, have suffered the worst and the most often due to tsunamis. The regularity of volcanic eruptions and undersea earthquakes in the “ring of fire” region means that this part of the globe will see tsunamis every single year.
The infamous 2004 tsunami triggered by an earthquake in the Indian Ocean, killing over 227,000 people:
But even if you are landlocked you are not necessarily safe from tsunamis. Places as diverse and far from the shore as Spirit Lake, Washington, and Tafjord, Norway have both experienced devastating mega-tsunamis dozens and even hundreds of feet high.
In the case of the Spirit Lake tsunami, it corresponded with the 1980 eruption of Mount St. Helens. A significant fraction of the mountain broke off resulting in major landslides that surged into Spirit Lake.
This gargantuan displacement of water created an 800ft. high tsunami. The Tafjord tsunami was similar in effect; occurring after a 2.6 million cubic yard rockslide from the Langhamaren Mountain plummeted into the Tafjorden, immediately generating a 200+ foot tsunami which killed 40 people near the shores.
It is a grim prospect, but anytime and anywhere you are near the shore of a major body of water you are technically at risk of a tsunami should that body of water be displaced by any means. You should be especially on guard if you’re near the shore of the Pacific Ocean or the Caribbean.
Another tsunami in Indonesia in 2018:
What About Seiche Waves? Are Those Tsunamis?
No. Seiche waves occur in fully- or semi- enclosed bodies of water, typically lakes, bays or gulfs.
Seiche waves are not created by the displacement of water as with a tsunami, but are instead the result of atmospheric phenomena, typically wind and changes in atmospheric pressure.
Wind will often push a portion of the water to one side of the body or the other, resulting in a drop on the opposite side. When the wind stops, the water rushes back to the far side, resulting in powerful currents and waves. The longer the water has to travel to restore volume, the more momentum it gathers.
Many times, these waves are not even noticeable, and certainly don’t do any damage. But in larger bodies of water, like the North American Great Lakes or Lake Wakatipu in New Zealand they can get bad enough to result in flooding and damage.
They even periodically cause deaths near the shore. Large and powerful seiche waves can even damage bridges and underwater cabling.
- Earthquake – Earthquakes commonly precede and cause tsunamis.
- Sudden Drop or Rise – An unusually timed, rapid rise or fall in water level is a sure indicator of a tsunami.
- Roaring or Rushing sounds – Some locales report hearing a sort of whooshing or freight train-like sound prior to the arrival of a tsunami.
- A sudden, small surge – Tsunamis often strike the shore unevenly, and one area might be barely drenched while another is annihilated. Follow-on waves may be different!
Unfortunately, tsunamis are not as easy to reliably predict as tornadoes and hurricanes. The mechanics behind their generation and sustainment are still not entirely understood.
Some massive and easily detectable undersea earthquakes will not create a tsunami while other, far smaller and weaker earthquakes may generate dreadfully powerful tsunamis. This means you’ll need to be alert for any potential clues that a tsunami is incoming.
Governmental and scientific agencies have implemented tsunami alert systems in various parts of the world though, again, these systems are not one hundred percent reliable even if they detect an earthquake that typically results in a tsunami.
In North America, NOAA weather alert radio will notify you of an official tsunami warning, and today many Coastal localities have similar systems in place.
If you are in a place that does not have such warning systems (or you don’t have access to them) you should always be on guard immediately for a tsunami in the aftermath of an earthquake.
If you can feel the ground shaking, even a little tremor, as soon as it is over you must take action. Additionally, keep your eyes and ears perked for any events that might cause a tsunami.
News of a major asteroid impact somewhere in the ocean or a scheduled or unscheduled nuclear detonation should immediately have you thinking about tsunami avoidance protocols.
Barring any of that, there is one symptom of tsunami that is fairly common. If you were lounging on the beach with your toes in the sand, sipping your pina colada at a coastal bar, and noticed the tide pulling out suddenly and far, or rising quickly atypical of the normal tide schedule, there’s likely a tsunami incoming.
Any tidal recession that exposes more sea bottom that is typically seen in that area is a major clue. While this does not always occur, should you notice it you must take action at once! You may have only minutes before the tsunami arrives!
Tsunami Incoming! Take Action!
If you receive an official warning, or perceive one of the warning signs typically heralding the arrival of a tsunami, you must act at once.
Do not take pictures, do not try to gather your things, do not “wait and see”: drop everything, and head for safer ground. Tsunamis are difficult to see coming if they present at all prior to landfall.
If you are in a boat, your response will be dictated by how close you are to shore. If you’re very close to shore or dock, your best bet is to put ashore quickly and head inland as fast as possible or get far above the ground in a strong building by any means. If you are a little ways from a dock, your best bet is to actually head out to sea.
Remember, most tsunamis are not the gargantuan waves traveling across the ocean that we see in disaster fiction. The farther you are from shore the less affected you will be by the moving mass of water. Things only get really bad as the mass of water piles up and grows taller when it reaches land.
A tsunami can be anywhere from 10 to 100 feet high when it reaches land and travels at least 20 miles per hour. An event of this magnitude often leaves very little time for reaction.
For this reason, most disaster readiness agencies recommend you get at least two miles inland and 100 feet above sea level if you can.
Also, you must never forget but, even after the water recedes from the initial impact, it is statistically likely there are several more waves incoming and the initial wave is rarely the strongest of them!
Subsequent waves may arrive in minutes, or even hours later. If the tsunami was caused by an earthquake, aftershocks may trigger additional tsunami “trains.”
When you get to safety stay there until you are certain all danger has passed!
Your Tsunami Preparation and Response Plan
The following tsunami prep guidelines are from the United States Department of Homeland Security and FEMA, and will help you get ready to avoid and survive a tsunami in three distinct phases: Before, During and After.
The aftermath portion is especially important since your troubles won’t end when the waters recede. Plenty of water will be left behind on land, soaking and inundating everything that was not destroyed, overturned or broken.
You can expect all roads to be underwater or buckled, power to be out everywhere, and water and sewage services to be compromised and out of commission.
Preparing Before a Tsunami
You’ll have much to do if you will be visiting or live in a tsunami-prone, or just a tsunami-vulnerable area. Do not neglect these crucial steps as they will inform much of your response plan.
- If you live in or are visiting a particularly tsunami vulnerable area, take the time to ask officials about any emergency plans, evacuation zones and escape routes. Movement by road is often the fastest way to get away from the water, but many routes maybe clogged or overwhelmed with other people trying to escape so you should look for alternates.
- Likewise learn if there are any particular warning signs of tsunamis for that specific area. Some communities report hearing loud roaring from the ocean, or seeing strange behaviors prior to the arrival of most tsunamis. Any of these signs or symptoms could serve as valuable early warning indicators for you.
- Understand, learn and, most importantly, practice any official evacuation plans on the prescribed routes from where you are staying, living or working. Reaction time is always a factor in surviving a tsunami.
- If at all possible, ensure that any chosen shelter locations are well above sea level (100 feet) and a minimum of one mile from the water.
- Take the time to create and implement an emergency family communication plan. Include at least one and preferably several emergency contacts that are out of the potentially affected area. Also vitally important, you should designate at least three meeting locations in case you get separated from your family.
- Sign up for any mobile tsunami warning services. In the United States, the Emergency Alert System and NOAA weather radio are two good and reliable choices.
- Also in the United States, you might consider obtaining earthquake and flood insurance if you live in an area that is vulnerable to or commonly affected by tsunamis note that most standard homeowner’s policies do not cover flood or earthquake incidents.
Survive During a Tsunami
Recall that most tsunamis occur as a result of earthquakes. You’ll need to deal with that before you take action to evade the tsunami that is likely to follow.
- If an earthquake is occurring: Drop, Take Cover and Hold On! Cover your head. Wait until the quake stops before you head for safe ground and take care when exiting damaged buildings.
- If you are not within a tsunami hazard zone remain in place and wait for official instructions.
- If you are within a tsunami hazard zone get to the highest ground available as far from the water as possible. DO NOT WAIT FOR OFFICIAL WARNINGS! If you cannot move inland quickly you must take cover using the highest and strongest vantage available. If there are no buildings around, climb the strongest, tallest tree in sight.
- If the water is within sight be alert for signs of an incoming tsunami. This could be rapidly rising or rapidly receding water.
- Stay out of the tsunami/flood waters if at all possible. If you cannot, grab hold of something that floats readily.
- If possible, stay tuned into emergency notification systems via radio, TV or phone.
- If you’re in a boat and not very near shore, head as far out to sea as you can while facing any waves directly. In most cases, the tsunami will pass you by harmlessly.
- Above all if under a tsunami warning evacuate immediately! DO NOT WAIT!
Be Safe After a Tsunami
- Listen for any local alerts regarding the status of the tsunami, and a greater disaster situation.
- Do not enter the floodwaters if possible: the murky water left behind by a tsunami will contain all manner of dangerous debris and biohazards. If you’re in the water when a secondary wave hits, you are likely to be crushed or drowned.
- Remain alert for any possible electrical hazards in the water. Toppled power lines and underground cables can lethally electrify the water. Even standing water only ankle deep can deliver a lethal shock.
- Be wary of any tsunami or earthquake damaged building or bridge. Keep in mind that roads may buckle suddenly without warning. Even bare ground that is heavily inundated with water may become a trap.
- Landlines and cellular phone systems are likely to be compromised in the aftermath of a tsunami. What systems are operational will be completely clogged with traffic. Stay off the phone if at all possible and use text- or internet-based communication to reach friends and family.
The Tsunami Readiness Kit
A tsunami has a high chance of displacing you from your home or wherever you might be for several days. That means many preps you have carefully laid in at a fixed location will be lost or likely inaccessible.
It is vital that you have an easy-to-transport kit ready to go at a moment’s notice and if you are traveling, or away from home, that you keep it with you.
A standard bug-out bag may work great, but their typical size and weight could be liabilities when you need to move fast if you are not traveling by car. What might be better is something the size of a go-bag, or get-home bag concept.
In essence, smaller, leaner and lighter BOBs, a compact bag of this type is ideal for tsunami preparation as you can grab it and go with very little encumbrance. This way you will still have most of what you need to survive or shelter in place.
Consider packing the following items below:
You want a lightweight, energy-dense, long-life foods for your go bag. Beef jerky, trail mix, energy gels, and perhaps MREs removed from their main packaging are ideal here.
You might be in for a very long wait at your shelter location and you’ll definitely be missing meals.
At least one liter of water in a sturdy reusable bottle or canteen. Water is very heavy, but you’ll be seriously water challenged in the aftermath of a tsunami since the saltwater alone will inundate and ruin local water supplies by itself, to say nothing of all the debris and nastiness it carries along with it.
Of vital importance is a compact water filter that can allow you to make safe found water supplies. Consider something like the LifeStraw or Berkey water filter. Some water steri-tabs are also a good idea.
Flashlight / Headlamp
You can bet any amount of money that the power will be out in the aftermath of a tsunami. No prepper should be without a reliable EDC flashlight, and preferably a headlamp for hands-free work. Choose one that offers a good combination of brightness and longevity.
Remember that you can use either of these for signaling in a pinch. Be sure to include a thin lanyard for each of them so if you drop them you will not lose them into the swirling murk. Don’t forget spare batteries in a waterproof container!
These glow-rod gadgets are completely safe light sources, ideal for signaling or marking – and also good for cheering up kids. You can tie one to the end of a cord, and spin it over your head like a helicopter to signal aircraft with ease.
First Aid Kit
Your first aid kit should include items for trauma as well as minor injuries: Bandages, rolled gauze, ace wraps, antiseptic solutions, tourniquets, tweezers band-aids, first-aid tape and moleskin. Also include a variety of common medications.
The ideal size and weight of your tsunami preparedness bag precludes a proper tool kit, but you can get pretty close by choosing any of the excellent multi-tools with pliers on the market. If you want to go really lightweight, consider a Swiss Army knife.
Pry Bar, or Small Tomahawk
Aside from making solid defensive implements, either of these tools can be used for search-and-rescue operations, easily extracting people from buildings or vehicles.
A power cell or backup battery can help keep your smartphone and other devices online. If you have a rechargeable flashlight, and can help keep that juiced up.
NOAA Radio – (if you are in the U.S.)
Hand-cranked disaster notification radios will allow you to receive updates from authorities even if all other methods fail. The nicer ones even have built-in flashlights and USB power supplies so you can use them as dynamo generators for keeping other devices charged.
A flyweight tarp will allow you to use it as a ground cover or as a shelter. In a pinch it can also work great as a sun shade, or for catching rain to gather drinking water.
Nothing fancy here. Throw a hank of paracord into your kit so you have a way to hang your tarp, hoist objects off the ground and create lanyards.
Lighters / Fire Starter
You want some way to create a fire, no matter what it is. I prefer the ubiquity of Bic lighters, but you can always make a good case for the trusty prepper standby, the ferro rod.
Storm matches are another option, as they are completely waterproof and will light in any conditions. Don’t forget to include some tinder.
An emergency blanket, or space blanket, will help you stay warm if you get wet, and can also serve as a dandy reflector for a fire that can dry you, and your clothes, out in no time. Takes up almost no room, and weighs next to nothing.
Map and Compass
The landscape after a tsunami has blown through it is likely to look very different, and you should not count on knowing your way around.
An area map, regional topographic map and a compass should be considered mandatory. Also include a city road map with a national road atlas in the back of it.
Spare Underwear and Socks
The chances are good you’ll be moving around on foot after a tsunami, so make sure you take good care of your feet. Wet, filthy socks will accelerate and exacerbate foot conditions.
Having a dry pair to change into while the others dry is a good idea. Underwear, too, for the same reasons.
Your hands will be facing all kinds of hazards in the aftermath of a tsunami. Broken glass, twisted metal, splintered wood, nails, sharp rocks and shells, you name it.
At the minimum, a sturdy pair of technical gloves is recommended. You will likely be better off with a seriously thick and heavy duty pair of leather work gloves.
Pad and Pen / Pencil
Ideal for jotting down updates, notes, messages from others, and any other important information. The less you have to rely on electronic devices during the aftermath of a tsunami, the better.
If you’re smart, you’ll invest in a waterproof pad of paper as made famous by the Rite-in-the-Rain company.
You can depend on local information electrical infrastructure being down after a tsunami, and that means no credit cards, no debit cards and not even a gift card. Cash will be king.
You don’t have to keep this in your bag if you prefer to keep it on you, but you always, always want to have a nice wad of cash reserve for emergencies. In this case, an emergency just like a tsunami!
Tsunamis are tremendously powerful threats and surprisingly common. Compared to other disasters, early warning systems are not entirely reliable at predicting the occurrence and arrival of tsunamis.
This means that you will have to be on guard and alert for any signs that may clue you in to a tsunami’s arrival. If a tsunami is incoming, minutes matter and you must have a plan and execute it swiftly to stand a chance of survival.
Tom Marlowe practically grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, Tom has the experience to help civilian shooters figure out what will work best for them.