Ultimate tsunami lesson: Live or die

Today closes Tsunami Preparedness Week 2013. It's time to look back on what has been learned about tsunamis in the past year and the challenges of preparing for the next tsunami.

On Wednesday, North Coast counties conducted their 5th tsunami test. The test was a success -- not because everything worked correctly, but because problems were identified and now they can be fixed. If you live or work in a tsunami zone, you should have a National Oceanic and Atmospheric Administration weather radio. It provides you a personal "siren" right inside your home. On Wednesday, NOAA weather radio activation worked well. The Emergency Alert System successfully interrupted radio and television programming on participating stations. For the first time, the test message included both English and Spanish. A few stations had static and the message was hard to understand. Weather prevented the two Civil Air Patrol planes based in Oregon from flying, but the Humboldt and Mendocino flyovers and airborne announcements generally worked well. Most of the sirens went off but the automated triggers for some did not.

One of the issues identified in the test was how hard it is to get messages to young adults who are less likely to listen to or read local media products. We have yet to figure out how to connect with some members of the millennial generation who may be very selective about what they choose to tune in to.

In the last year, 13 tsunamis were noted in the world, one caused casualties, and only one produced a tsunami alert for Northern California. The Feb. 6 earthquake in the Solomon Islands killed 15 people. Like the majority of deadly tsunamis, the affected area was close to the earthquake and surges arrived only minutes after the earthquake. The low loss of life was attributed to the high level of tsunami awareness and the quick evacuation of most people after feeling the earthquake. Sadly, most of the victims were elderly and lacked the mobility to get out of harm's way.

Our North Coast tsunami alert came on Oct. 27, 2012, when it rudely interrupted the bottom of the ninth inning in Game 3 of the World Series. Our coast was placed in a tsunami advisory status after a magnitude 7.7 earthquake off the coast of British Columbia. This was the first tsunami to occur after the official launch of Google Public Alerts for tsunamis, a collaboration between Google and the tsunami warning Centers to quickly push alerts to the public. There were a few bugs in the automated message. The unfortunate headline read "Tsunami Warning for AK, British Columbia, US East Coast and US West Coast." Some people thought this meant we were in a warning and sent a flurry of postings to social media. I spent most of my evening trying to straighten out the confusion.

The most important tsunami lesson of the past year is the one I keep learning over and over. The only way to survive a tsunami is to evacuate if you are in a hazardous area. People survive when they take immediate action and evacuate; people die when they don't. This isn't as simple as it seems. How people perceive risk, process risk factors and decide to take action depends on what they know, what they perceive and how they process the information. The official warning system -- the sirens, radio and TV announcements, and airborne announcements like those tested on Wednesday -- is designed to get your attention and give you guidance on what to do. When the earthquake is nearby, you need to make sure that you respond just as quickly to natural warnings, such as an earthquake that shakes for a very long time or change in the ocean. Take the lead in evacuating and you will be not only a survivor, but perhaps our next tsunami hero as well.

Lori Dengler is a professor of geology at Humboldt State University and an expert on tsunami education and mitigation.


Sunday: Your first warning is when the ground shakes

Tuesday: This is a test -- a test of the tsunami communications system

Wednesday: How you can save a life during a tsunami

Thursday: Tsunami advice for inlanders

Friday: What may wash up on our shores

Today: Tsunami lessons learned and relearned