Curious Iowa: What does it take to sound outdoor warning sirens?

At 8:45 a.m. on the first Wednesday of the month, the Linn County Emergency Management Agency sets off its outdoor warning sirens for testing. A gravely computer-generated voice lets listeners know that a test is being conducted and they’re free to go about their days. But what does it take to test the sirens that sound during severe weather?

That’s what one curious Iowan wanted to know. Curious Iowa is a Gazette series that seeks to answer Iowans’ questions about the state, its culture and the people who live here. We set out to find what happens behind the scenes when a storm siren goes off.

Where did Linn County get its siren system?

The Linn County Emergency Management Agency (EMA) operates approximately 150 storm sirens. For context, the entire island of Maui in Hawaii has 80 siren towers.

Many of Linn County’s sirens were donated by NextEra Energy Resources, owner of the decommissioned Duane Arnold nuclear power plant in 2022. The sirens were previously placed throughout a 10-mile emergency planning zone around the nuclear power plant in Palo. In addition to the sirens, Linn County EMA received the plant’s maintenance shop and a bucket truck to help maintain the donated sirens.

Since the donation, the sirens have been strategically placed across the county, and more sirens have been added.

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Linn County EMA Operations and Readiness officer Tom Ulrich said the donated siren system was a boon for Linn County.

“A lot of communities say all the siren systems are outdated, mainly because they didn’t keep it up and they can’t afford to keep it running and they can’t afford new sirens,” he said. “That’s why we’re fortunate that we inherited an up-to-date modern siren system. We don’t have to go back and try to piecemeal anything together.”

Maintenance of the sirens costs $175,200 a year.

“We’re pretty thrifty with our parts,” Ulrich added. “We send them in to get fixed instead of ordering them brand-new.”

While it costs the county — and, thus, taxpayers — money to maintain the system, Ulrich said he knows they’ve saved lives.

“One was a family inside their house that, they heard the sirens and they had just … quit watching the news. They ran up and grabbed their kids. House came apart as they were going to the basement.” Ulrich said. “Had another one that was out working on the farm and the wife heard [the siren] from the house and started yelling at him. They got inside just as the building he was working in came apart.”

Why is regular testing and maintenance important?

While residents may be familiar with the monthly audible test of the storm sirens, Linn County runs less public tests of the sirens weekly. Siren Technician Ron Jarrett said the tests produce detailed reports that show whether batteries, speakers and amplifiers, among other things, are working.

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All of Linn County EMA’s sirens receive annual maintenance. Batteries are replaced every three years but the battery status is checked annually. Additional maintenance can include things like cutting back weeds around the base of the siren pole or removing the gooey, dirty nest of an ant colony that has moved into the electronics box.

“It’ll take a couple years but [ants] will take you down eventually,” Jarrett said.

This level of testing and maintenance is not standard in every community and Linn County EMA takes pride in its extensive outdoor warning system. Jarrett said that in some towns with fewer resources, maintenance happens when they run a test and the sirens don’t sound.

What would warrant sounding sirens?

Linn County EMA follows statewide protocol when determining whether to sound its alarms. Ulrich gave examples of when a siren would be used:

“We don’t ever second guess the National Weather Service,” Ulrich said. “They are the experts.”

Who confirms severe weather?

Weather is unpredictable and sometimes when warning sirens are sounded, the severe weather doesn’t materialize.

“I get people that call and say, well, tornado didn’t hit,” Ulrich said. “Well, thank goodness, but the atmosphere was there and the weather service issued a warning so that’s why we set off the outdoor warning system.”

During severe weather events, Linn County EMA communicates with the National Weather Service and TV meteorologists in a chat room “so everybody’s on the same loop,” Ulrich said.

In addition to working with those experts, Ulrich said Linn County has a “strong network of weather spotters” who work with Linn County EMA during severe weather. This includes volunteer and paid fire departments, as well as amateur ham radio operators.

One of those storm spotters is Linn County Amateur Radio Emergency Coordinator Lee Garner. Garner said the purpose of the amateur radio emergency service program is to supplement communications when needed, whether that is confirming hail or setting up a “net” on the airwaves to share what resources are available after a derecho.

Licensed amateur radio operators can talk to each other and broadcast information on radio frequencies reserved for amateur radio by the FCC. There are approximately 1,340 licensed amateurs in Linn County and 6,620 licensed amateurs in the state of Iowa.

Storm spotters are trained through the National Weather Service’s SKYWARN Program. The training teaches spotters to give weather reports in a way the National Weather Service would want to receive them, Garner said.

“[H]aving reports from the community from the ground can give information that could be needed from specific locations or can confirm what is being reported through their instrumentation and data,” Garner said.

Ulrich said that during severe weather events, Linn County EMA will bring in an amateur radio operator as a liaison, fielding weather confirmations from other AR operators. These ground view reports inform Linn County EMA’s response to severe weather.

Why is there a voice with Linn County’s sirens?

The only time listeners will hear a voice with the Linn County EMA sirens is during the monthly test. In the past, there was a voice with emergency warnings that told listeners to take shelter immediately. That voice was removed so that people wouldn’t leave their shelter to hear what the voice on the warning was saying.

Ulrich said the voice on the tests is intended to alert visitors to the area that the sirens are being tested. The voice message can be difficult to understand because sirens rotate. The message is repeated four times.

“So you may be able to hear it clear one time and then the rest of the time it’s going to sound like … somebody’s got their hand over their mouth,” Ulrich said.

Ulrich stressed that when sirens are used to warn of severe weather, an “all clear” signal will never be blown.

“If it goes off a second time, it’s because the warning expired and they issued a new one.”

Why can’t I hear the sirens in my house?

Outdoor warning sirens are used to alert vulnerable populations to move inside. Ulrich said Linn County is the home to an abundance of trails, parks and campgrounds. Those natural areas may fall in pockets where cellphone service is not available. Sirens are used to tell campers, hikers and people working outside to seek shelter and find more information on what is going on.

Ulrich said people should have multiple ways of receiving emergency alerts. Sirens are one way. Cellphone apps are another, though he warns that cellphone alerts can be missed.

“How many phone calls have you missed this week?” Ulrich said. “The average person would have missed a few … you would have missed that alert.”

Though a storm siren going off could also be ignored, Ulrich said, “It should send a chill up your back when a siren goes off.”

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Comments: bailey.cichon@thegazette.com