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Sirens Remain Vital to Hawaii’s Emergency Alert System

Hawaii is retrofitting its entire emergency siren network, moving to satellite and cellular control technology.

by / May 14, 2013
Adam DuBrowa/FEMA

In an era where people rely on mobile devices for information, a warning siren may seem like outdated technology. But in Hawaii, a new retrofit program will ensure that the booming outdoor alarms will continue to serve as the state’s primary emergency alert system for years to come.

Hawaii is in the midst of a $25.6 million overhaul of its statewide warning siren network. Once the project is complete, 490 sirens will be spread throughout the state, including 205 on Oahu, the most populous of the Hawaiian islands. The sirens will operate on a state-of-the-art satellite-cellular communications system.

The investment could be seen as a surprise by some, particularly since sirens have increasingly been disregarded by people on the U.S. mainland in favor of other types of alerts.

For example, when a tornado laid waste to Joplin, Mo., in May 2011, resident Jose de Leon told The Joplin Globe that he heard the tornado siren but chose to ignore it, as did many others in the area.

In an interview with Emergency Management in 2011, Jon Martin, professor and chair of the Department of Atmospheric and Oceanic Sciences at the University of Wisconsin-Madison, believed approximately 25 percent of the 535 deaths caused by spring tornadoes in 2011 could have been because people failed to heed warning sirens.

Despite the flippant attitude toward sirens by some people, Tom Simon, systems engineer of Hawaii State Civil Defense, said sirens are absolutely needed in the state. He explained that tourists and residents aren’t always carrying a smartphone to receive geo-located emergency notifications and even if they are, signal strength may be suspect in a mountainous or elevated region.

“Because of the amount of time people here in Hawaii spend outdoors and … the potential for tsunamis, we are still putting a lot of emphasis on our siren system,” Simon said. “If you’re on the beach and you don’t happen to have your cellphone, you still need to know that it’s time to get away from the beach.”

Hawaii won’t solely depend on the sirens for emergency notifications, however. The state’s alert system distributes messages and emergency notifications over radio, TV and cable. Officials also can send text-like messages to cellphones through broadcast technology using the Wireless Emergency Alert service, formerly called the Commercial Mobile Alert System, deployed in April 2012 by the wireless industry, the FCC and FEMA.

Satellite System

The siren network modernization project consists of two parts. The first step is replacing the old radio-based technology at each siren site with the satellite-cellular control system. The second consists of replacing the sirens themselves. The sirens and control system are provided by Federal Signal.

Work began last year on Oahu, which is home to approximately 40 percent of all the sirens in Hawaii. Simon said they installed and tested the new system successfully on eight siren sites in 2012 and then proceeded with retrofit work on 143 sirens on Oahu. Six new siren sites will also be added in the coming months.

Maui County will be next, where 88 sirens need retrofitting or replacing, Simon said. The entire statewide project should be complete in 2014.

Hawaii’s old siren control system ran through VHF wideband radio. All four counties used different types of control systems, which was a drain on state resources. Technicians had to learn how each one worked and how they needed to be maintained.

George Burnett, telecommunications branch chief of Hawaii State Civil Defense, said one of the main reasons the state opted to upgrade satellite-cellular technology was because the separate county control systems were incompatible.

He added that most of the mechanical sirens in operation around Hawaii are 25 to 30 years old and well past their usable life cycle, which was a critical factor in moving forward on the upgrade project.

“The sirens were no longer maintainable,” Burnett said. “We were having to go to extraordinary lengths to get parts, rebuild motors and things like that, which were very difficult to accomplish.”

According to Simon, the radio system’s transmitters also needed constant alignment adjustments to give a clean signal. Technicians were spending an inordinate amount of time on the task. That will no longer be a problem with the new control technology.

The new satellite-cellular system allows the state to standardize siren control and provides redundancy. If the satellite signal has interference, it immediately jumps to the cellular signal as a backup, ensuring that downtime is virtually nonexistent. SkyWave is providing satellite communications, while Verizon will handle the cellular signal.

Efficiency Gains

In addition to increased redundancy, workers can now access informative data on the status of each siren’s condition. In the past, the only time the state would know a siren was malfunctioning was if a resident noticed that a siren didn’t go off during a monthly test and called it in, or during twice yearly preventive maintenance visits.

With two-way communication, technicians can more efficiently track and address maintenance issues as they arise. The sirens are solar powered and each use four deep-cycle batteries. Technicians can now be miles away and check items such as battery voltage, whether the charger is working and even receive notifications from the siren if someone tries to break into it.

“I would say our sirens are in much better condition now based on the information we’ve been able to get through the system and the [technicians] having time to go out and fix them,” Simon said.

The satellite-cellular connection also lets the state test the system without disturbing residents. Simon said “quiet tests” can be conducted during which the siren is given instructions to activate at a frequency that’s too high for anyone to hear, but give the state a reading on the amplifiers’ output. Once complete, the results can be reviewed to determine if the sirens are working properly.

“In the few months we’ve had this working on Oahu, we’ve found this additional information has really helped the technicians go out and get more of the sirens fixed more quickly,” Simon said. “They’re working almost immediately after we find a problem, instead of not knowing.”

Looking Ahead

While the installation process went fairly well on Oahu, there were some expected bumps along the way. Since the control system was completely new, there was a bit of a learning curve as technicians became familiar with operating it. Federal Signal also had to tweak the system to address minor connectivity issues. 

Since the sirens use satellite signals as their primary source of communication, the area around the sirens must be clear of vegetation. That can be a problem in Hawaii. Simon explained that because there’s a lot of rain throughout the islands, certain locations can experience rapid overgrowth.

Although that typically doesn’t affect cellular communications, it can interfere with satellite coverage. So existing siren sites had to be evaluated, and when looking into new locations, officials had to factor vegetation into consideration.

In addition, using satellite communication causes a delay from the time the siren is activated by state personnel until it actually goes off. The state synchronizes its monthly test of the siren system with a radio broadcast. But once the siren is activated, it takes 30 to 45 seconds before it sounds, which could be confusing to the average resident.

The delay shouldn’t matter during an actual emergency, however. Since disasters are usually unexpected, people wouldn’t know when the button was pushed, so an extra 30 to 45 seconds before the siren starts would likely have a negligible impact on safety.

The U.S. military has also taken note of Hawaii’s siren upgrade. The Army, Navy, Air Force and Marines all have bases in Hawaii and depending on the branch, either work in conjunction with the state to issue emergency warnings or use their own system.

Simon said Joint Base Pearl Harbor-Hickam has its own radio control system, but one of the siren sites activates automatically off the state’s signal. The Army, he said, is in the process of doing something similar. 

Photo courtesy of Adam DuBrowa/FEMA. This story was originally published by Emergency Management magazine.

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Brian Heaton

Brian Heaton was a writer for Government Technology magazine from 2011 to mid-2015.

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