Getting fast, comprehensive and accurate information is crucial during emergencies like the devastating wildfires still raging in the Los Angeles area. And over the last two terrifying weeks, one app has become the place to find it: Watch Duty. Operated by a nonprofit, the app was launched in 2021 to track wildfires in Northern California and now provides coverage for more than 20 states. Marketplace’s Meghan McCarty Carino spoke with David Merritt, Watch Duty’s chief technology officer, about how it all came together.