As devastating fires continue to rage in the Southern California area, an app that tracks wildfires with live maps and alerts has become the No. 1 free app in Apples App Store.Watch Duty, launched in 2021 and used by firefighters and first responders across the western United States, surpassed the ChatGPT app, Lemon8, and Threads for the top spot as of Wednesday morning. Across social media, concerned citizens and Los Angeles residents encouraged others to download the free app for updates about nearby wildfires and firefighting efforts. One X user posted, In 24 hours, I went from never having heard of Watch Duty to checking the app religiously.The app, which is run by the Santa Rosabased nonprofit Sherwood Forestry Service, has already added 600,000 new users in just the last 24 hours according to CEO John Mills. Watch Duty is powered by a team of volunteers and staff, including active and retired firefighters, dispatchers, and veteran storm watchers. The team uses automated alerts sent to its Slack platform whenever a 911 call is made regarding a fire. They actively monitor fire-related developments by listening to radio scanners, reviewing wildlife cameras and satellite data, and tracking official updates from law enforcement, fire services, and other public sources.The apps interface uses a color-coded system: dark red for active fires or burned areas, light red for mandatory evacuations, and yellow for evacuation warnings, signaling users to prepare for potential orders. However, its important to remember the app is not a replacement for official information.Whats happening right now in L.A. is the worst that Ive seen in the five years Ive been doing this . . . This is catastrophic, Mills told The Los Angeles Times. Its really hard to watch, but Id rather be doing this than not doing anything. It feels like we could at least do something to help, because otherwise were just sitting here watching the world burn.Mills was motivated to launch the app by his own experiences of wildfires after moving to Sonoma County in 2020. During the 2020 Walbridge Fire, which burned to the edge of his property, he relied on Facebook groups for updates and wondered if there was a better way to share information. Since its launch, Watch Dutys downloads have skyrocketed as climate-related weather events continue to impact communities. In December, the app said it increased its yearly active users to 7.2 million from 1.9 million in 2023.The Los Angeles fires, driven by dry conditions and strong winds, are currently causing widespread devastation beyond the immediate danger zones. As of Thursday morning, at least five people have died and over 130,000 people have been ordered to evacuate as the fires continue to spread.