A Tsunami (pronounced soo-ná-mee), also known as a seismic sea wave, and much less accurately as a “tidal wave”, is a series of enormous waves created by an underwater disturbance such as an earthquake, landslide, volcanic eruption, or meteorite. A tsunami can move hundreds of miles per hour in the open ocean and smash into land with waves as high as 100 feet or more.
Most of the world became aware of just how destructive Tsunamis can be in March of 2011 when Japan experienced a devastating Tsunami that was the result of a 9.0 earthquake that occurred in Honshu. The Honshu quake generated a tsunami observed over the Pacific region that caused tremendous local devastation. The quake that spawned the Tsunami was the fourth largest earthquake in the world and the largest in Japan since instrumental recordings began in 1900. This is the deadliest tsunami since the 2004 magnitude 9.1 Sumatra earthquake and tsunami which caused nearly 230,000 deaths and $10 billion in damage.
All tsunamis are potentially dangerous, even though they may not damage every coastline they strike. A tsunami can strike anywhere along a country’s coastline. In the U.S., the most destructive tsunamis have occurred along the coasts of California, Oregon, Washington, Alaska, and Hawaii.
What to do Before a Tsunami
Whether or not you need to prepare for a Tsunami, of course, depends on where you live. If you live in any coastal area, a possible tsunami should be part of your risk assessment, especially if you live in an area such as the coastline of California that is also prone to earthquakes, or volcanic activity such as in Hawaii or other Pacific Island chains.
As with any potential natural disaster that can destroy your home, or cause you to evacuate, the first thing you need to do to prepare for a Tsunami is Have a Plan, Make a Kit — including a Go Bag for every member of your family — and Stay Informed. As always, you need to talk to everyone in your household about what to do if a tsunami occurs. Create and practice an evacuation plan for your family. Familiarity may save your life. Be able to follow your escape route at night and during inclement weather. Practicing your plan makes the appropriate response more of a reaction, requiring less thinking during an actual emergency.
Since Tsunamis can follow any earthquake event, even after a mild quake if you are in a coastal area, turn on your radio, or TV to learn if there is a tsunami warning. In addition:
- Have your Go Bag(s) and your Bug Out Vehicle gassed and prepped to go at a moments notice
- You need to know if your children’s school evacuation plan requires you to pick them up from school or from another location. Be aware telephone lines during a tsunami watch or warning may be overloaded and routes to and from schools may be jammed.
- You need to know all of your community’s warning systems and disaster plans, including Tsunami evacuation routes.
- You need to know the height of your street above sea level and the distance of your street from the coast or other high-risk waters. Evacuation orders may be based on these numbers.
- If you are a tourist visiting an area that could be threatened by Tsunamis, you must familiarize yourself with local tsunami evacuation protocols, and the plan for your specific hotel or vacation residence.
If a Tsunami Watch Has Been Issued
- Use your NOAA Weather Radio or tune to a Coast Guard emergency frequency station or a local radio or television station for updated emergency information.
- Locate household members and review your evacuation plans. Be ready to move quickly if a tsunami warning is issued.
If a Tsunami Warning Has Been Issued
- Evacuate at once.
- Be sure to take your Go Bag(s) with you, having supplies will make you more comfortable during the evacuation.
- Get to higher ground as far inland as possible. Watching a tsunami could put you in grave danger. If you can see the wave, you are too close to escape it.
During A Tsunami
If a tsunami warning has been issued your best chance of survival is to Bug Out for higher ground along your pre-determined evacuation route ASAP! Do not leave your pets behind; if it is unsafe for you, it is unsafe for them. Take only what you have prepared in your Go-Bag, the goal is to save yourself and your family, not your possessions.
- Move inland to higher ground immediately. Pick areas 100 feet (30 meters) above sea level or go as far as 2 miles (3 kilometers) inland, away from the coastline. If you cannot get this high or far, go as high or as far as you can. Every foot inland or upward may make a difference.
- Stay away from the beach. Never go down to the beach to watch a tsunami come in. If you can see the wave you are too close to escape it. CAUTION – If there is a noticeable recession in water away from the shoreline this is nature’s tsunami warning and it should be heeded. You should move away immediately.
After the Wave Recedes
As in the wake of any Natural Disaster only return home after local officials tell you it is safe. A tsunami is a series of waves that may continue for hours. Do not assume that after one wave, the danger is over. The next wave may be larger than the first one.
- Go to a designated public shelter if you have been told to evacuate or you feel it is unsafe to remain in your home.
- Unless local authorities have asked you to because of your particular skills, avoid disaster areas. Your presence might interfere with emergency response operations and put you at further risk from the residual effects of floods.
- Stay away from debris in the water; it may pose a safety hazard to people or pets.
- Check yourself for injuries and get first aid as needed before helping injured or trapped persons.
- If someone needs to be rescued and is not in immediate danger, call professionals with the right equipment to help. Many unskilled and untrained people have been killed or injured trying to rescue others.
- Continue using an NOAA Weather Radio or tuning to a Coast Guard station or a local radio or television station for the latest updates.
- Stay out of any building that has water around it. Tsunami water can cause floors to crack or walls to collapse.
- Use caution when re-entering buildings or homes. Tsunami-driven floodwater may have damaged buildings where you least expect it. Carefully watch every step you take.
- To avoid injury, wear protective clothing and be cautious when cleaning up.
- Be sure to watch your animals closely and keep them under your direct control, they can panic in areas that have become unfamiliar in the aftermath of a Tsunami Event.
If you live on any coast you must be aware that a potential Tsunami is one of the prices that is paid for the luxury of a coastal lifestyle. But, understanding how to prepare for and react to a Tsunami is important for everybody, and not just people who live on the coast. The fact of the matter is many of us chose to vacation in coastal resort areas, and as recent headlines have shown, such resorts are not impervious to Tsunami events. And in fact, many of these resort areas are made more vulnerable due to the fact that they are in countries that may not have as well of a developed infrastructure, or emergency response, as you might find at home.