Tsunamis can be very, very bad. Caused by earthquakes, underwater landslides, volcanic eruptions, or asteroid strikes, these massive waves absolutely devastate coastal areas. They can take out all infrastructure in minutes, and almost everyone caught in a large tsunami’s waters will die. The 2004 Boxing Day tsunami killed over 230,000 people in Thailand, Sri Lanka, and Indonesia.
If there’s anything good about a tsunami, it’s that there’s often enough warning to give you a fighting chance at survival, if you’re prepared, smart, and fast. Below are some rules of what to do before, during, and after a tsunami.
Advanced preparation for a tsunami
The number one rule of tsunami survival is simple: Head for the hills — move inland, to higher ground — so if you’re near a coastline, you need to know where the closest hills are and when you should head for them.
- Understand the risks: A tsunami could hit any coast, but some places are more vulnerable than others. In the United States, Alaska, Hawaii, and the northern coastal areas of California are in the greatest danger, but nowhere is safe: The Boxing Day tsunami came ashore in places with no warning systems and no previous history of tsunamis. The last victims of the Boxing Day disaster were drowned eight hours after the quake that caused the tsunami, in South Africa, 8,047 km away from the epicentre.
- Research community evacuation plans: Some communities have tsunami evacuation plans for the public. Learn what they are.
- Check out the National Tsunami warning system: Here’s the link.
- Plan an escape route: Take some time to figure out the best tsunami escape route if you live or spend a lot of time near the ocean. The basic rule: Find the quickest way to get to higher ground.
- Get flood insurance: If you live near the coast, insure your house for flooding. Regular home-owner insurance generally doesn’t cover flood or earthquake damage.
Recognise the signs of an impending tsunami
There are two types of tsunamis: distant tsunamis and local tsunamis. A distant tsunami might be caused by an earthquake far out to sea, and can have a warning time of five and half to 18 hours. That’s enough time for official evacuation orders to get to you, provided you’re somewhere with a warning system in place.
Local tsunamis are caused by earthquakes and other natural events closer to shore, and might have a 5 to 30 minute warning time. These are the ones where recognising the signs of an approaching disaster could save your life.
- Emergency broadcasts: If a tsunami is caused by a distant event, the first warning sign is likely to come as an emergency broadcast or other warning through official channels. Take these seriously.
- Earthquake: If a tsunami is generated close by, your first sign might be feeling the earthquake. If you’re near the beach and a quake hits, once the ground stops shaking and it’s safe to move, get to high ground. Don’t wait to be told. Just go. The longer the ground shakes, the more likely it is to generate a tsunami, but don’t try to determine the chances: just go. If you’re wrong, at least you practiced your escape route.
- Rapidly receding water: Watch for rapidly receding ocean water that goes back further than you’d expect. If the ocean starts rolling backwards, so fast you can see it, or so fast that fish are beached as you can see in this video, you need to get to high ground immediately. Do not stare at the ocean receding while wondering what is happening. Do not collect fish.
- Wave on the horizon: You can see them coming, but an approaching tsunami might not look like you’d think. “It’s a wave, but from the observer’s standpoint, you wouldn’t recognise it as a wave,” Vasily Titov, a tsunami researcher and forecaster with the National Oceanic and Atmospheric Administration Centre for Tsunami Research, told history.com “It’s more like the ocean turns into a white water river and floods everything in its path.”
- Listen for a roar from the ocean: If you hear a loud noise from the ocean, it’s either a tsunami or the wrath of Poseidon. Either way, you should run.
A tsunami is on its way…what now?
- Take action: Do not look to other civilians for cues as to whether to worry about a potentially approaching tsunami — tourists on a beach are particularly clueless — just head for higher ground.
- Decide how much obligation you have to help others: You might feel the need to help others escape an oncoming natural disaster, but should you? You probably don’t know what you’re doing, and you could die, so instead of playing hero, maybe yell “Get inland! There’s a tsunami coming!” over your shoulder as you run.
- If you are swimming: If you feel a sustained earthquake while swimming, it is not your lucky day. Try to grab onto something that floats — a piece of wood, a raft, etc. — if you can but, well…things do not look good.
- If you are in a boat: According to the government, if you are in a boat and a tsunami is approaching, “face the direction of the waves and head out to sea. If you are in a harbour, then go inland.”
After the tsunami
If you headed inland and uphill at the first sign of receding water, first pat yourself on the back for acting quickly and decisively. Then:
- Listen to authorities: Listen to radios for official information about what to do, where you should head to a shelters, and any other instructions.
- Stay out of the flood water: Water from a tsunami is filthy, filled with harmful chemicals and diseases, and could even be electrified. Do not touch it, drink it, or swim in it.
- Don’t go near damaged buildings: Staying away from unstable structures is a good rule for any situation.
- Be sparing with the cell-phone usage: Cell phone networks can get bogged down during disasters. Send texts or use social media to let people know you’re OK. Only call for emergencies.