Cellphone emergency alerts aren't foolproof. Could blaring sirens help during the next big fire?

Cellphones these days are for everything, and one of their most important functions has become emergency alert systems.

Cellphone alerts are far from foolproof, though, as we experienced during January’s devastating fires. In west Altadena, warnings came too late or not at all. Cell service went out in many cases. Not everyone has access to a smartphone or is signed up for alerts.

And if a disaster hits in the middle of the night, cellphones are likely to be off or silenced.

After January’s fires, many survivors I spoke with asked: Why don’t we use tornado sirens like communities in the Midwest to warn of fires?

The answer, as usual, is complicated. Like any alert system, public education — and trust — is key. And sirens can’t replace cellphone alert systems, which are more targeted and can be easily accessed by most people, if they're signed up.

Emergency management officials and a fire battalion chief said sirens can be a life-saving tool when cell service goes out or amid widespread power outages.

While sirens may make sense for certain communities and can fill gaps in digital emergency alerts, they’re far from a silver bullet. Experts cautioned that sirens have limitations, such as:

• They can be impossible to hear from inside double-pane or triple-pane windows, especially with a TV on or for people with hearing impairments. 
• Topography that blocks cell service — rolling hills, mountains — can also block the sound of sirens.
• They’re expensive and require ongoing maintenance.
• They can be confusing without proper public education. For example, Maui officials chose not to use Lahaina’s siren system during the deadly 2023 wildfires because they were worried people would think the alert was for a tsunami and end up heading toward the flames. 

LAist asked the L.A. County Office of Emergency Management if officials might consider sirens, but it declined to comment until an after-action report about the January fires is complete.

“The McChrystal After-Action Review is taking a comprehensive look at the capabilities the county possesses to alert and warn the public during emergencies,” a spokesperson for the office wrote to LAist. “Upon release of findings, we will look at the recommendations to see what improvements or enhancements to our alerting tools can best serve our communities.”

A brief history of sirens

Sirens were first developed for another type of disaster — war. You can find remnants of World War II and Cold War-era air raid sirens in cities across Southern California. In the mid-20th century, such sirens were novel technology. Some cities and towns eventually used them to alert other disasters and to call volunteer firefighters to stations.

But between the 1980s and mid-2000s, many of these aging sirens were decommissioned because they required costly maintenance — and because newer, more targeted technologies replaced them.

An air raid siren that was installed in Van Nuys in 1956.

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Courtesy L.A. Public Library

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At the same time, these sirens became less effective as cities sprawled and buildings modernized. For example, newer standards of double- and even triple-pane windows makes it hard to hear even today’s sirens from inside with the windows closed, said David Acuña, a battalion chief and public information officer with the California Department of Forestry and Fire Protection, or Cal Fire.

With the rise of pagers, and then cellphones, sirens largely went out of vogue, he said.

“Sirens were the technological advancement in the 1920s, 1930s, 1940s. Instead of having to go door-to-door, now we get to have the siren,” Acuña said. “Technology has surpassed that since then.”

L.A., for example, decommissioned its air raid siren system in 1985.

Sirens in an age of worsening wildfire

As wildfires grow hotter and more destructive, and the limits of cellphone alerts continue to be revealed, many communities are reconsidering sirens.

Take, for example, Paradise in Northern California’s Butte County. In 2018, the Camp Fire razed the town, killing at least 85 people. At the time, Paradise had the CodeRED phone alert system (and still does), but that fire led to cell service going out, and many people said they didn’t receive alerts.

The community is still recovering today. As part of that recovery, Paradise decided to invest in 21 sirens, which, nearly seven years later, are up and running.

An outdoor warning siren in Paradise, Calif.

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Courtesy Paradise

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The new warning sirens in Paradise can be disguised as trees.

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Courtesy Paradise

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The sirens sound up to 90 decibels and can be operated manually via internet or satellite. They’re hardwired to power underground, but also have solar and battery backup power.

But they are really only audible outside, and the ability to hear them can decrease dramatically just a slight distance away, said Mayor Steve Crowder, who lives about a quarter mile from one siren and couldn’t hear it well from inside his house during tests.

“People were looking to be able to hear them from inside, with windows closed and not all of them have hit that mark,” he said.

To solve for that, the town got additional funding to purchase transmitters that can be placed inside residents’ homes. If the sirens go off, those will too. Paradise plans to distribute them this year, Crowder said.

“It's not going to be a cure all, but it's sure going to make it a lot more efficient and I think make everybody a lot safer,” Crowder said.

But the cost is high: The sirens were a little over $3 million, funded by a Federal Emergency Management Agency grant. The town found additional funding for the transmitters.

The rest of Butte County decided to go another route — a technology called AlertFM, which uses FM radio signals instead of cell service. (The county also still uses CodeRED mobile alerts — redundancy is key in emergency planning, experts say).

An AlertFM receiver.

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Courtesy AlertFM

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The county has so far distributed more than 1,500 receivers for free, and received an additional $400,000 grant to distribute another 1,500 units. People can also buy their own for about $100.

“ A majority of the citizens, the sheriff and the board felt that AlertFM was the best bang for the buck — of course, as long as people adopt them,” said Butte County Supervisor Doug Teeter.

That technology has similar limits as cellphones and sirens — FM signals can be blocked by terrain.

“ How do you reach folks that don't have their cellphone? That's the purpose of the sirens and AlertFM,” Teeter said. “I don't think there's going to be a perfect solution. It's just a challenge that we face in trying to be able to reach everyone at a moment's notice.”

It’s why emergency experts say the most important thing is for individuals to be aware of their surroundings, have their own escape plan (and practice it), and expect that sufficient warning or help may not come in the case of a catastrophe.

Why Malibu decided against sirens

The city of Malibu also considered installing sirens after the 2018 Woolsey Fire. But a feasibility study found residents couldn’t hear them in high winds, hilly terrain and indoors.

The 20- to 30-foot towers can also be an eyesore, and the cost was estimated to be from $426,000 to nearly $2 million.

“The problem we're trying to solve for is how do we wake up people in the middle of the night when cell service is out,” said Susan Dueñas,  the city’s public safety director. “Depending on the wind, the construction of your home, your hearing, all these factors, you may not hear it. So they are a very expensive investment for something that didn’t look like it was going to solve the problem.”

The types of warning sirens can vary. But terrain and modern building standards can mean that they are difficult to hear indoors.

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Malibu Siren Feasibility report

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The city also considered AlertFM, but that came with its own set of challenges and an upfront cost for a five-year licensing agreement of $960,000. And the main radio station in the area, KBUU, had too weak of a signal to reach most of Malibu’s residents. So the city invested in the station, installing a booster antenna last year.

“The coverage is better, but people aren't able to hear it in their homes, so that's a problem,” Dueñas said. “The signal's not strong enough to get into somebody's home.”

That’s why the city is currently surveying residents about AlertFM reception. The city of L.A. is also giving Malibu two mobile speaker trailers. L.A. purchased six through a federal grant.

But none of this is meant to replace cellphone alerts, home hardening or plain old preparation and awareness, Dueñas said.

“We wish there was a magic answer that would just solve the problem. No matter what we do, we're going to have to use a number of tools, not just one,” she said. “Government can't be there to save every person, sadly. That's why people need to have a plan.”