Back in March of 2011, a 9.0 magnitude earthquake in Japan triggered a tsunami, and then a Tsunami Warning for much of the California coast.
At the time the basic tsunami evacuation plan said a Warning should trigger the worst case scenario evacuation. This left county emergency managers with two options: order an evacuation of everyone in the tsunami flood zone or do nothing.
Why even consider doing nothing? Because the 2011 warning came at a time of low tide.
“It didn’t reach the point of flooding dry land in California during that time frame, even though we were in a warning,” says Kevin Miller of the Tsunami Program in California’s Office of Emergency Services.
“Whereas, if it were at high tide and you added another six, seven feet in some locations, that would’ve made a difference of night and day in terms of pushing water onto land and putting more people into danger and forcing the need for evacuation,” Miller continues.
A new state report co-authored by Miller, says emergency managers need more detailed options taking into consideration things like tides and potential wave height.
Krista Almanzan (KA): So, what are the tools that were developed over the last couple of years that give emergency managers more to work with than all or nothing?
Kevin Miller (KM): So we have developed what we’re calling tsunami evacuation playbooks, which are less than maximum tsunami evacuation zones. Basically they have a new set of maps that are for those three to four scenarios in between the all or nothing situation.
So for instance, there would be phase 1, a phase 2. That phase 1 would evacuate people just at the coast, phase 2 would evacuate people further inland. Phase 3, additional people and depending on the size of the tsunami it would apply to a specific phase of evacuation.
Now if were in a warning situation at high tide, with less than five hours, we’re not going to apply this tool. We are going to say use your basic plan and use your maximum evacuation line. But if we have more time, say ten hours, and it’s a less than worst case scenario, then it would be appropriate to apply this playbook.
KA: So who has these playbooks?
KM: We’ve provided those for Monterey, Ventura, Humboldt, San Diego and Orange as our initial first five counties, and over the next year or so through calendar 2016, we’ll be providing those to the rest of the counties in California.
KA: We all rely on emergency managers for guidance in situations like this, but what can we do as individuals?
KM: Anyone can go online and find out where their hazard zone is and where their safe zone is, and potentially practice getting from point A at the coast to point B 100 feet inland, that's a few feet higher, and understanding where that is can be key to some basic safety should you hear or feel a warning.
KA: Is there any rule of thumb for how far it is to be safe?
KM: A rule of thumb is a mile inland and 50 feet up.
To view Santa Cruz County and Monterey County tsunami flood zone maps, click through to your desired neighborhood and download the pdf.