Tsunami Warning Signs You Should Know

By Richard Hannibal, Retired Police Sergeant

On March 21, 2011, during a tsunami warning, Morro Bay (CA) experienced a tidal surge of 8 to 9 feet. An earthquake in Japan caused the surge that may be the highest in memory on the California Coast. A tsunami can occur on the west coast anytime there is a severe earthquake in the Pacific. Following are some signs you should know that might save your life.

The Japanese coined the word tsunami to mean, "harbor wave" ("tsu" means harbor, and the character "nami" means wave). In the wake of the Japanese tragedy, remember these tsunami survival tips:

1. A good warning sign of an approaching tsunami is "drawback." That is when the ocean recedes drastically or the water level falls unusually low along the shoreline. During the 2004 Indian Ocean tsunami, a 10-year-old girl on vacation with her family in Thailand, Tilly Smith, saved the lives of dozens of tourists when she recognized the receding water and frothing bubbles on the surface of the water as a sign that a tsunami was on it’s way. Experts believe that a receding ocean may give people as much as five minutes’ warning to evacuate the area.

2. You are not out of danger after the first wave of a tsunami hits shore. A tsunami occurs as a series of waves known as a "wave train." The series of surges can be five minutes to an hour apart. A tsunami does not usually appear on the shoreline as a gigantic breaking wave, but rather as a rapid tide or a wall of water. The worst mistake you can make is staying near the beach out of curiosity. Find higher ground, and go as far inland as you can. If you can see the waves, you are still too close!

3. A tsunami surge may be small at one point of the shore and large at another point. Move to higher ground as soon as you can and do not assume that because there is minimal activity in the coastal area where you are, it will be like that everywhere else.

4. Keep your ears peeled. Many witnesses have said that a tsunami sounds thunderous, like a freight train.

5. The depth of the water determines a tsunami's ability to maintain speed. A tsunami moves faster in deeper water and slower in shallower water. So unlike a normal wav e, the driving energy of a tsunami moves through the water as opposed to on top of it. Therefore, as a tsunami moves though deep water at hundreds of miles an hour, it is barely noticeable above the waterline. A tsunami is typically no more than 3 feet (1 meter) high until it gets close to shore. Once a tsunami gets close to shore, it takes its more recognizable and deadly form. In San Luis Obispo County, the cities, and towns of San Simeon, Cambria, Cayucos, and Morro Bay are at high risk of tsunami damage and loss of life. Remember, head for high ground, and do not delay out of curiosity. In addition, if there is an evacuation ordered, do not forget the homeless folks living in the creek-side camps near the shore.