PARADISE, Calif. — California residents driven from their homes by one of the deadliest wildfires in recent history had one request before they would rebuild in the small mountain town of Paradise: warning sirens to bolster town emergency systems that failed some people before the fast-moving inferno that killed 85.

Town officials started testing the new sirens this summer after installation began in spring and as the five-year anniversary of the wildfire that wiped out much of the community approaches this November. There will eventually be 21 sirens erected throughout town that will emit one minute of loud, Hi-Lo warning sounds followed by evacuation instructions.

“If you’re going to come back to town, if you’re going to be part of Paradise again, what would make you feel secure and happy and wanting to come back? What do you need?” Paradise Mayor Greg Bolin recalled asking residents after the fire. “Number one on that list was a warning system.”

Tests of the sirens began in July and are run on the first Saturday of every month. Twelve sirens were ready for testing in early August, at locations ranging from Town Hall to police headquarters to remote intersections. The town’s protocol says the sirens and messaging will sound for 10 minutes, followed by intervals of five minutes of silence and five minutes of warnings “until the emergency has subsided.”

Reliable, audible warning systems are becoming more critical during wildfires of increasing speed and ferocity, especially as power lines and cell towers fail, knocking out communications critical to keeping people informed. After 2017 fires that ripped through California’s wine country, killing dozens, residents complained they got little to no warning from officials, who used phone calls and other alert systems but did not deploy a widespread cellphone alert. Many residents of Paradise had the same complaint.

Even when siren systems are in place, officials must make the choice to activate them.

Hawaii Authorities Failed to Activate Sirens

Officials in Hawaii failed to activate sirens last week, raising questions about whether everything was done to alert the public in a state that devised an elaborate emergency warning system for potential dangers that include war, volcanoes, hurricanes and wildfires. On Maui, a fast-moving wildfire has killed more than 100.

As in Paradise, some people tried to flee Lahaina but perished in their cars after getting stuck in traffic gridlock.

In Paradise, the Camp Fire broke out in the early morning of Nov. 8, 2018, amid dry, gusty weather. It tore through the town of 28,000 people, incinerating roughly 19,000 homes, businesses and other buildings. An investigation determined Pacific Gas & Electric’s aging equipment started the blaze and the utility pleaded guilty to 84 counts of involuntary manslaughter.

Many residents said they received no warning on their cellphones or landlines as the fire quickly spread their way. They jumped in their vehicles to escape only after seeing smoke and flames, or after relatives or neighbors knocked on their doors.

“If that fire would have happened just a few hours earlier than what it did, we would have had hundreds of people die from that because they’d have been in bed,” Bolin said.

The new sirens, similar to a tsunami warning system, are being incorporated into the city’s emergency services, which include mass cell notifications, an emergency call center for people to call, and an AM radio station to broadcast public safety information.

Paradise’s siren system can be controlled manually, over the internet, or by satellite. The towers’ power is hard-wired underground, but each siren also has a solar panel that can store two weeks worth of power.

“We’ve got back-up after back-up on these,” Bolin said.

University of California forest expert Yana Valachovic said the redundancy in emergency services is needed to address different scenarios.

“We cannot guarantee that we’ll have power and cellphone communication capacities so, every community needs a full toolbox of resources,” she said.

Authorities also need to consider designating temporary refuge areas and practice evacuating their communities at different times of the day, she added.

As part of rebuilding Paradise, crews have removed thousands of trees, cleared defensible space around homes to slow down fires, buried power cables underground, and widened evacuation routes to handle more traffic, Bolin said.

Like Paradise, communities across California are coming up with systems to notify people in case of an emergency, from sirens to police patrol cars and other emergency vehicles to cellphone notification systems. In May, officials in Santa Rosa, where the wine country fires broke out, tested a new cellphone alert system. In March, Beverly Hills began installing 12 outdoor sirens. Sonoma County has installed a sophisticated fire camera system to detect blazes early.

The California Office of Emergency Services in 2019 issued alert and warning guidelines for counties. It warns sirens can have limited effectiveness because people inside well-insulated homes and buildings may not hear them well.

“If a public siren is used for alert and warning, it should include an extensive public outreach campaign to train residents and visitors on what the siren means and the intended protective action,” it says.

Jen Goodlin, a Paradise native and director of Rebuild Paradise who moved back after the fire to help with the reconstruction, said she supports the sirens because many in the community don’t have easy access to the internet or media.

Having the sirens “is a way to help them escape sooner. It makes me feel safer,” Goodlin said.