Though tsunamis had certainly crashed against shorelines in the past, the sheer damage and death that this one wrought to Indonesia brought the terror and reality of tsunami destruction to our television screens.
Since the mid 1900's, over smaller tsunamis have done damage in North America along the West Coast, including Alaska, and Hawaii.
With "mega-disasters" seeming on the increase, there may be some catastrophic tsunamis heading our way -- like the tsunami resulting from the earthquake that struck Japan on March 11, 2011, killing thousands and causing the meltdown of the Fukushima nuclear power plant -- which lead to mass evacuations from the region.
Japan´s Tsunami - Caught on Camera - Documentary 2011 USA - video footage of tsunami
One of the truly crazy things about tsunamis is that in the open ocean they could literally pass right under ships and be undetected. This is because they are only a few feet high out at sea, even if they are hundreds of miles long.
Despite the fact that the amplitude of a tsunami is usually very small in the open ocean ( making tsunamis hard to detect with the naked eye ) when they are about to touch down on land, their height increases. Oftentimes upon landfall they reach 10-20 feet in height, but severe tsunamis have reached heights greater than 100 feet. Of course, a tsunamis' speed decreases as it is about to impact with the land.
Last, low lying communities are at most risk for damage from these natural disasters waiting to happen. In fact, the word tsunami comes from the Japanese word for "harbor wave." Thus, they are quite well known in that area of the world for destroying many of Japan's low lying harbors throughout their history.
In such instances, you should realize that The West Coast / Alaska Tsunami Warning Center ( WC/ATWC ) is there to help warn you about impending tsunamis. The website and information is put out by the National Oceanic and Atmospheric Administration. Further, you can sign up for updates via email at the website.
Simply put, the WC/ATWC looks for earthquakes or activity with the potential to cause tsunamis and then contacts appropriate emergency personnel in affected areas. Thus, having a radio on you when out may not be a bad idea if you live in a tsunami zone.
Then proceed as emergency personnel have told you to (usually outside the problematic area or to an evacuation shelter of some sort). It is important to stay calm during evacuation. Further, it is also important to remember that you should evacuate to a place of higher ground.
2. A severe earthquake just before the tsunami can knock out phone lines and cell towers and of course electricity. If that happens, you'll have no way to get in contact with others. Consider having a few pairs of two way radios for family members in the area to get in contact with each other should an earthquake this bad take place.
3. If you are in a school, do what the school staff tell you to. This would seem obvious, but apparently isn't always so.
4. If you are on the beach or somewhere within a tsunami zone and feel an earthquake, do not wait for a warning. Immediately move away from the low lying area to a higher one. Keep in mind that if this occurs, you may have only minutes to move to higher ground.
In other words, stay calm but be quick! If there is a regional earthquake, sometimes a warning will not be posted before the tsunami hits home.
5. Another well known precursor to a tsunami is that the tide will often roll out extremely quickly and far. Know this. However, if this occurs you likely have very little time before the tsunami hits. So, evacuate to higher ground immediately.
6. If you are on the beach and an earthquake or some other tsunami warning sign occurs, it may be prudent to keep in mind that multi story hotels with concrete reinforcement may provide a safe haven.
2. If you are in port, it might be advisable to communicate with the harbor authority (if there is one) on what to do.
3. If you are in port and there is no harbor authority to rely on, owners of small boats might be advised to leave their vessels and move to higher ground. Owners of bigger boats will have to decide whether they have the time and desire to move their boat to deeper water in a calm and orderly manner.
Whether or not global warming could cause more tsunamis in the future is unclear. What's strange about the Global Warming theory is this: Global warming doesn't cause earthquakes. I'm not sure how anyone can call this increase in catastrophic disasters we're seeing soley caused by Global Warming.