Human error. That's the most plausible explanation being given by emergency planners as to why some Oahu neighborhoods never heard a siren blast announcing Saturday's tsunami warning.
"The initial siren activation for the county of Oahu was made using an older siren system that was still in place," explained John Cummings, spokesman for the city's Department of Emergency Management. "Once we realized what had happened, the next siren sounding and subsequent siren soundings…were made using a newly installed computer-controlled system put in place by Hawaii State Civil Defense."
There are 180 emergency sirens scattered across Oahu, and according to State Civil Defense spokeswoman Shelly Kunishige, 91 sirens are still operating under the older radio-activated system.
The new computer-based model can activate emergency sirens through cellular and satellite technology, which is considered more reliable. The effort to convert 291 of Hawaii's 318 sirens to the more advanced system is costing $2 million, with $959,000 of the funds being spent on Oahu.
Until the conversion is finished, city officials have come-up with a solution that would allow all sirens to be activated as soon as possible. If time is of the essence, the Honolulu Police Department will trigger all 180 sirens through a separate control panel located at police dispatch on South Beretania Street.
"That would give our staff time to get into the office, get activated, and then take control of the system after that," said Cummings, who expects an agreement with HPD in short order.
Reports of sirens malfunctioning or being too faint to hear have been received from Kaneohe, Kalihi Valley, Laie, Makakilo and Oahu's North Shore. Honolulu Mayor Peter Carlisle agrees giving HPD the authority to activate sirens is a step in the right direction.
"I think we have to think that way because there are circumstances where we could be inundated by tsunami waves even quicker than we did this time," said Carlisle. "Particularly, if something dramatic happened on the Big Island, or one of the other neighbor islands, or somewhere in between."
James O'Shea, who lives near Rocky Point in Haleiwa, told KITV4 he was at a neighbor's house for a children's Halloween party when the first siren blast was activated at 7:55 p.m., about two-and-a-half hours before the arrival of the first wave.
"We couldn't hear the sirens," said O'Shea. "It wasn't like there was a loud party or anything; we just couldn't hear the sirens at all."
O'Shea said news of the tsunami warning was spread mostly by word-of-mouth among neighbors. However, at 8:05 p.m. he received a text message on his phone from the city's Nixle service saying all coastal areas should evacuate.
"So that's kind of a backup system too," said O'Shea. "I didn't hear my first siren until I was down by Sharks Cove driving to evacuate, and that was not until 10:05 p.m. or so."
Cummings said while emergency sirens are important, they are only a part of the state's multifaceted emergency alert system. He said it's up to residents in tsunami inundation zones to stay informed through TV and radio broadcasts, as well as social media sites like Facebook and Twitter.
"We have a tsunami threat here in Hawaii," said Cummings, "It's nothing new."
Saturday's tsunami warning was triggered by a 7.7 magnitude earthquake off the Canadian west coast near British Columbia just after 5 p.m. Hawaii time. So far, there have been no reports of damage throughout in Hawaii or elsewhere.
The largest tsunami wave recorded in Hawaii was 2.5 feet at Kahului Harbor on Maui. That was followed by 1.4 feet in Haleiwa, and 1.3 feet in Makapuu.
Meanwhile, the city is standing by its decision to urge drivers out of their cars if they found themselves in a tsunami inundation zone less than a half hour before the first wave was expected to hit.
Shortly after 10 p.m. Carlisle told drivers to begin seeking higher ground on foot if they couldn't make it to a safer area in time.
"That's a very difficult decision to make that has to be done on a case-by-case basis," said the mayor. "We obviously saw what happened to Japan, and we cannot afford to be anything less than eternally vigilant."
Oahu residents can volunteer to monitor warning sirens in their respective neighborhoods through the adopt-a-siren program at: http://sirens.honolulu.gov/.
To sign-up for the city’s Nixle alerts, go to: http://local.nixle.com/register/?cc=honoluludem