Paulette Lifton woke up on her 67th birthday on Tuesday morning in a panic to smoke pluming in the distance of her home in the Granada Hills neighborhood of Los Angeles. The first person she called was her sister Annette.
“What’s going on?” Ms. Lifton asked.
“You have to download the Watch Duty app,” her sister responded.
Ms. Lifton did just that, tracking the spread of the fire through the app’s map and updates as she packed her car with her most prized possessions — her favorite sequin jacket; her dogs, King Charles spaniels, Elle and Sansa; and the two Emmys she won as a television and movie sound editor.
For Ms. Lifton and thousands of other Los Angeles residents, Watch Duty has become a lifeline in tracking the multiple wildfires blazing around the city. In a county of nearly 10 million people, the news of the app has spread by word of mouth and in online community groups.
The app has sometimes provided faster and more reliable updates than the city’s buggy mobile notification system.
On Thursday night, Los Angeles County’s alert system broadcast an erroneous evacuation alert to all residents in its jurisdiction, instead of just to those near the West Hills neighborhood, which was threatened by the Kenneth Fire.
Officials said on Saturday said that some county residents were getting outdated alerts after cell towers that had been taken offline during the fires came back online. Watch Duty, which has remained among the most downloaded free apps in the Apple App Store, has not had those issues.
Founded in 2021, the app has had 2 million downloads since Tuesday, and 14 million unique users this week, Watch Duty’s chief executive, John Mills, said in an interview on Saturday.
Mr. Mills operates the app through a nonprofit with a team of 200 volunteers and 15 full-time employees, including retired firefighters and dispatchers. That team listens to radio broadcasts from emergency responders and transmits live updates to the app, which maps the fires and delineates evacuation zones.
P.J. Marino, a 52-year-old actor who lives in the city’s Van Nuys neighborhood, downloaded Watch Duty on Tuesday night, and his phone was soon hit with a barrage of notifications. He found himself waking up in the middle of the night to check it and has since made multiple posts on social media urging his neighbors to download it.
“It’s morbid, and I hate that I have to use it,” Mr. Marino said. “But it’s necessary.”
Cara Mia DiMassa said she and her neighbors used the app’s map to track the Eaton Fire, which spared her home but destroyed the Altadena summer camp that she owned with her family.
She said it was “absolutely” a better tool for tracking the fires than the official notices from the government, then added that the app can be chaotic. She had to turn off its notifications to sleep at night.
Mr. Mills, an entrepreneur who lives in Northern California’s Sonoma County, said he’s had to evacuate from fires three times in his life. He said he built Watch Duty because the government has never provided something with the same utility.
The app collects very little personal data from users, he said, adding that he runs it through a nonprofit because he has no intention of selling it.
“This is my life and my community,” he said. “I owe it to my community to not be a disaster capitalist.”
Watch Duty is mostly funded by donations and has grown in recent years as wildfires across the West Coast have become more common and intense. The app currently provides coverage in 22 states west of the Mississippi River, not including Alaska or Louisiana.
Mr. Mills said he isn’t worried about the app’s network being able to support the influx of users because he has enough volunteers and employees to staff the service around the clock.
“When things go sideways, this is what we’re here for,” Mr. Mills said. “And we’re not close to done.”
